Internal Trade

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Internal Trade

BIBLIOGRAPHY

In most countries internal trade ranks second or third among types of industries generating the national product, but it has been a stepchild of economic analysis. Early classical economists considered productive activity to consist of form-changing only. Marx added consideration of the labor input into transport, warehousing, and other physical handling. But, in the Soviet Union, as consumer goods have become more plentiful and varied, retailing has come to include display of goods, salesclerk time to provide information, and even some competitive advertising (Goldman 1963, pp. 191-200). Non-Marxian economic theory has long recognized that consumer satisfaction (and hence production) is enhanced by trade among specialists at various steps in commodity production and by the service of distribution that puts finished goods in a certain place at the time that users want them. But in the development of price and output theory, economists have dealt primarily with the structure and performance of the raw-material and manufacturing industries (or with transport and electric power) and have treated these as if manufacturers sold finished products directly to consumers or, alternatively, as if the distributive trades were analytically neutral. Except in an occasional empirical study (e.g., Adelman 1959, pp. 109-149, 248-274), the distributive trades have been neglected in their roles as buyers from, or as potential entrants into, supplying industries (whereby they influence significantly the performance of earlier-stage markets), or as resellers that affect the information provided about, and consumers’ choices among, goods made by rival manufacturers. This lack of economic analysis and the general confusion about the economic function of the distributive trades have contributed in no small part to the question asked in the book Does Distribution Cost Too Much? (see Twentieth Century Fund 1939), which is answered affirmatively there and elsewhere.

Trade as part of production. Transactions between autonomous ownership units make possible and are augmented by specialization in commodity production. A primitive household producing all that it consumes does not engage in trade. But once some goods are supplied by others there is trade, even though the maker of the goods is himself the seller to consumers. Long before recorded history, when a locality produced a surplus of a commodity traders distributed the goods elsewhere. The industrial revolution greatly enhanced specialization by, and transfers among, establishments, firms, and localities involved in the various vertical steps from raw material to finished consumer goods production. While such transfers can occur between establishments in common ownership (even within the government, say), trade ordinarily connotes exchanges between autonomous units whose activities are coordinated through market transactions. Indeed, internal trade differs from international trade only in that the latter involves transactions beyond the boundaries of a sovereign political authority, which ordinarily imposes restraints on trade that inhibit geographic specialization in production or, alternatively, the geographic mobility of labor and capital.

In the broad usage, including transportation, warehousing, and advertising, internal trade accounted for about 40 per cent of the value of goods as bought by all final buyers in the United States in 1947 (Cox et al. 1965, p. 148). Of the total value of all articles supplied to households, internal trade accounted for almost 43 per cent (ibid., p. 145). Nearly 12 of these 43 percentage points were accounted for by trading activities of the nondistributive industries, chiefly those producing commodities. The remaining 31 points were attributed to the distributive industries—3 of these points represented value added by transportation and storage, almost 2 were added by advertising, and the residual of almost 27 per cent was provided by the wholesale and retail industries (adapted from Cox et al. 1965, p. 145). Because this is an estimate of “value added,” it excludes the distributive trades’ purchases of supplies, power, fuel, transportation, and advertising, and, for this reason, is much lower than the composite wholesale-retail gross margins cited below. Were comparable data for other countries available, they probably would reflect the degree of specialization in commodity production among ownership units and the comparative efficiency of such productive activities and of trading.

The economic function of the distribution to consumers of goods in final physical form consists of providing the satisfaction of “place and time utility” —to which one can add “information utility.” Manufacturers perform part of these services by packaging goods, receiving orders, and shipping or arranging transportation. Some would include manufacturers’ advertising and sales personnel costs (Twentieth Century Fund 1939, pp. 6, 7); but much of this activity is directed to persuading consumers to buy manufacturer A’s brand rather than B’s on grounds other than clear-cut superiority—the form of rivalry elected because the structure of some manufacturing industries lessens or estops price competition [seeOligopoly]. Further analysis will be directed, therefore, primarily to the wholesaling and retailing of finished goods to households and other small-scale purchasers.

Because commodity production is more specialized geographically than are the locations of consumers, commodities must be assembled from many areas and a stock held in the locality of consumption. This is the function of wholesaling, whether done by a manufacturer’s branch, an autonomous enterprise, or a purchasing-warehousing operation owned by one or by many retailers. Making the goods available at the specific place and time consumers prefer and providing some information are the functions of retailing. Only then is production in the economic sense complete.

The “price” of the distributive service. Symmetrical with the distributive trades’ product is the “price” of the distributive services, which is defined as the gross margin between invoice cost of the good landed at the wholesaler’s or retailer’s establishment and the resale price. This margin is usually expressed as a percentage of the latter.

When analyzing economic performance of a distributive trade, the article-by-article gross margins are not as important as is the margin obtained on a group of articles or even for a type of outlet as a whole. Most costs of wholesaling and of retailing are both common and joint among the goods handled, although there is some opportunity in the long run to alter what is handled. But the selling in the same space and by the same personnel of items that have similar purchasing characteristics from the consumers’ point of view, although they may differ widely in consumer use, means that selling one food is facilitated by simultaneously offering other foods and other household articles that consumers’ behavior indicates they prefer to buy in the same outlet. Consequently, the intensity and elasticity of demand for the service of various retailers reflect primarily consumer preferences among composites of prices, locations, and qualities of service offered by retailers of families of articles.

The gross margin is a weighted average of margins on the various articles in the group. For example, the storewide gross margins of large-chain food retailers (including purchasing and warehousing operations) averaged about 15 per cent in early 1942, but the average margins for individual dry-grocery articles in the United States (as found by the Office of Price Administration 1943) ranged from about 7 to more than 20 per cent. Such differences must reflect the net outcome of rivalry among food stores, each of which seeks, as a multiproduct firm, to adjust margins on various articles so as to maximize the return on its investment in retailing (Holdren 1960). But the social performance consists of the efficiency and price of the distributive service for families of articles or for the whole outlet.

Distribution as a share of gross output. Distribution does cost much or, it is equally correct to say, produces much. “Trade and commerce,” identified as primarily wholesale and retail trade but explicitly excluding transportation, contributes between 6 and 20 per cent of the gross product of most nations (circa 1958). The percentages are positively but not highly correlated with per capita output (United Nations 1963, pp. 491-497; Yearbook of National Accounts Statistics 1962, pp. 314-317). The chief exceptions to this correlation are the high shares of trade in total output in most Mediterranean countries and the low shares reported for communist countries, of which more later. But using the percentage of the labor force employed in retailing to indicate distribution’s share, the correlation with per capita gross product is high in western Europe (Jefferys & Knee 1962, p. 13). A similar indication is the higher general level of retail margins in the United States than in Great Britain (Hall et al. 1961, p. 50).

In the Western countries the share of wholesale and retail distribution in total economic activity has risen generally with historical advances in output per capita. This can be deduced from the small increase in sales per person engaged in these activities from 1910 to 1950 in the United States and Great Britain (Hall et al. 1961, p. 10) compared to the known much sharper rise over this period in productivity in commodity production. A similar inference can be drawn from the advance in the ratio of employment in distribution to employment in commodity production over recent decades in western Europe (Jefferys & Knee 1962, p. 10) and over an eighty-year period in the United States (Barger 1955, p. 8), and from the substantial rise from 1869 to 1909 in distributive margins for most commodity lines in the United States, followed by a very slow upward creep to 1948 (ibid., pp. 8, 38, 57, 60, 70, 77, and 81). This is consistent with the increase from 1929 to 1958 of distribution’s share of the gross national product of the United States—with government activity omitted (Cox et al. 1965, p. 53).

Productivity in distribution . There is no fully satisfactory measure of the output of the distributive trades. The physical volume of goods sold at retail, weighted by distributive margins in various lines of trade, is affected by differences in the quality of distributive service among times, places, and types of outlets. (These defects do not affect the significance of distributive margins themselves insofar as differences in quality of service affect costs.) Retail sales per person engaged are the only data available for most comparisons and, after adjustment for price level, can be quite useful. Both measures show similar changes in output per person engaged in the United States from 1910 to about 1950 (cf. Barger 1955, p. 38, with Hall et al. 1961, p. 10).

Economies of scale. Economies of size are quite limited for the individual retail outlet but not for the firm. Measured by sales per person engaged in food and in shoe retailing in Britain and the United States, efficiency is substantially higher for moderate-sized shops than for small ones but very little higher, and in some cases lower, for large stores (Hall et al. 1961, pp. 66-70). Gain from large size is limited by the added costs of advertising, or the lower gross margin, needed to attract more customers to one location.

A firm of more than very small size usually engages in multisite operations, but neither British nor United States data show clearly higher sales per person engaged (except for food stores) in shops of a given size for chains above about ten outlets (Hall et al. 1961, pp. 66-70; and as computed from U.S. Bureau of the Census 1957). U.S. food chains report ratios of operating expenses to sales for the composite of their purchasing, warehousing, and retailing (Earle & Sheehan 1966, pp. 14-15) that vary inversely with firms’sales volumes. But these differences are related to the fact that the smaller chains buy to a large extent through wholesalers and therefore pay somewhat higher prices for goods that are delivered to their stores.

The observed success of large-chain retailers stems primarily from lower invoice cost of goods, which is achieved through skill in purchasing combined with volume enough in each locality to turn wholesaling into a logistics-type warehousing operation. An important phase of purchasing is specification-buying, or even own-manufacturing, of goods to be resold under a chain’s own brands. Chains have also gone far in rationalizing the retailing step but they clearly did not initiate important innovations at that step. In Britain, Canada, and the United States giant chains have no clear advantage over those of moderate size in the distribution (but do at times in procurement) of food and of low-priced clothing, furniture, and hardware, when providing qualities of articles and of distributive service consumers expect at the prices charged. Offsetting changes in organization and practices of the few-store chains and of single-outlet retailers have slowed down large-chain growth, as will be seen below.

Historical changes in productivity. In substantial degree the historical rise in distribution’s share of gross output reflects the lesser advance in productivity in distribution than in commodity production. In the United States output per worker in commodity production in 1949 was over five times the 1869 level but in distribution less than twice (Barger 1955, p. 38). In western Europe sales per person engaged in distribution rose sharply between the 1930s and the late 1950s, but the ratio of employment in distribution to that in commodity production rose nevertheless (Jefferys & Knee 1962, pp. 10, 45).

As real incomes rise in advanced countries distributive margins tend to account for a higher percentage of the retail value of consumer goods. In addition to the much less rapid advance of productivity in distribution than in commodity production, there is the fact that at higher income levels a larger proportion of consumer demand is for goods for which retail margins are relatively wide (Barger 1955, p. 131). Hence distributive margins for most types of goods rose historically in the United States (the only country for which long-period estimates are available), particularly prior to World War I (ibid., pp. 81, 84, 92). For the same reason, distributive margins were substantially higher in the United States than in Britain in 1948-1950 (Hall et al. 1961, p. 26), except in food distribution where innovation in the former country had reduced labor input sharply.

In Great Britain and the United States post-World War ii margins ranged from a low of about 20 per cent for food up to more than 40 per cent for furniture and jewelry (Hall et al. 1961; Barger 1955, p. 81). Even with food declining in relative importance, the composite distributive margin for all goods sold at retail in the United States rose substantially prior to World War I (Barger 1955, p. 92). After that date, innovations in distributive organization and methods, chiefly in food distribution, and the lower quality of retail service provided by the burgeoning mass distributors, slowed down the advance of the composite margin on all goods.

The very low distributive costs, of about 7 per cent of retail prices, reported for the Soviet Union do not reflect corresponding efficiency. By including in retail sales a turnover tax of about 40 per cent of retail prices, the denominator in computing distribution costs as a per cent of retail sales volume is enlarged correspondingly. (General retail sales taxes are not included in reported retail sales volume in the United States, for example.) After eliminating the Soviet turnover tax and making other adjustments so that the data are more comparable with those for the United States, the Soviet percentage is doubled but even then remains far lower. The very low quality of retail service and high proportion of all consumer goods that consists of food (the lowest-margin category in the United States) in communist countries vitiates comparison of over-all distributive costs and margins between them and advanced capitalist countries. Recently, the added variety of consumer goods and the lessening of rationing by queues, plus higher quality of retail service, have led to an upward trend in distribution costs in the Soviet Union (Goldman 1963, pp. 84-167).

For reasons cited in the preceding paragraphs, available data do not permit precise comparisons of the efficiency of finished good distribution among commodity lines, among nations, or for a given nation at different dates. But much of value can be concluded for free enterprise economies from the developments in and characteristics of distributive trade markets and of consumer behavior.

Current performance of distributive markets . While productivity has advanced more rapidly in commodity production than in distribution, a fundamental innovation in organization, often called “mass distribution,” has altered the size of retail outlets, influenced even more the size of the firm and the degree of vertical integration, and worked toward lower gross margins. Starting in the United States in the last century, primarily in food but extending progressively to apparel, “hard goods,” and selling by mail, the innovation spread to Canada decades ago, then, after a considerable interval, to Britain and Australia, but not to western Europe until after 1945. It has not yet been adopted widely in other countries.

The innovators saw the operating-cost savings made possible by high-turnover retailing, usually with sales for cash only and often with reduced service, both in retail stores and by mail (Adelman 1959, pp. 25-50; Emmet & Jeuck 1950, particularly chapters 3, 8, 21).

Preconditions for these cost savings, particularly of self-service, were prepackaging by manufacturers and consumer purchase by description, usually by brand, because of conviction of quality fostered by advertising and not refuted by experience. Success led to the adding of stores to which the word “chain” or “multiple” was applied. Firms attained substantial volume and, aided by developments in transportation, communication, and record-keeping, integrated from retailing into the warehousing function and began to buy from primary sources. Distribution changed from a three-stage movement—from a wholesale stock to a retail stock to consumers—to a flow movement with inventories minimized at all stages. Little room was left for the traditional general line wholesaler.

In the United States the food chains’ (11 or more stores) share of sales rose from approximately zero in 1869 to more than 40 per cent in 1962, bringing a sharp reduction in the weighted average of chains’ and independents’ distributive spread for food (Barger 1955, p. 92). This fact, together with the relatively narrower margins of chain and mailorder sellers of lower-price apparel and some “hard goods,” contributed to the relative stability of the composite distributive spread for all consumer goods since 1910. A quite similar growth of chains’shares, but probably not in cost savings, has occurred in Great Britain and a major start has been made in western Europe since 1945 (Jefferys & Knee 1962, pp. 49-71).

Belatedly, by adopting analogous organization and methods, many independent retailers and wholesalers are now able to at least come close to matching the chains’ costs and prices. Many retailers have cooperatively integrated into wholesale warehousing or have joined “voluntary” groups that contract to purchase from a sponsoring wholesaler. They can therefore buy the goods landed at their establishments at prices comparable, or nearly so, to those paid by chains (Jefferys & Knee 1962, pp. 76-83; Heflebower 1957, p. 276). These arrangements enable retailers to get the advantages of large-scale buying by specification, and of group merchandising of the owned or associated wholesaler brands. So that they will have the necessary scale a group of small food chains in the United States own a cooperative buying-merchandising enterprise. Numerous independent retailers have adopted the chains’ retailing method of rapid turnover achieved by low prices and lesser service. Reorganization of the wholesaler-independent retailer arrangement and changed practices in retailing have slowed down but not everywhere checked the growth of the chains’share of retail volume. The revived independent retailer performance and rivalry among the chain food stores have held the latter’s net profits (after corporate income taxes) to about 1 per cent of sales in the United States and to 10 per cent of equity (Earle & Sheehan 1966, pp. 9, 19), a modest earning rate for this generally highly prosperous postwar period.

Monopolistic competition. The typical local retail market tends to be strongly but not perfectly competitive in the short run [seeCompetition]. Much of the imperfection stems from the small size of markets geographically, for, despite the fact that the efficient scale of retailer outlets is not large absolutely, often it is large compared to the volume of trade that can be attracted to one site without sharply rising costs. The very few outlets handling similar families of articles in a shopping center are not fully restrained by the possibility of entry of an additional seller, for the capacity added would tend to force down margins and make entry uninviting even though the capital required is quite small. But established stores in a shopping center often experiment with handling added product lines—a form of entry. Finally, where consumers can easily shift from one shopping locality to another, a ceiling on prices in each center is imposed.

On the other side of the market, consumers choose between the gain, in the form of better (in their opinion) combinations of distributive service and price, from added search, and the cost of that search, which consists chiefly of time expended (Stigler 1961, pp. 218-224). Once a shop has been found to be optimal however, repeated purchases involve zero search costs. Consumers also tend to be passive and to respond only to the attention-getting devices of sellers, of which store display has proved very effective. Furthermore, the marginal cost of search tends to be correlated positively with level of consumers’ incomes because of the time required to acquire information about the added types and varied character of the goods bought out of the higher income. At the same time, the marginal satisfaction from making better purchases falls, ceteris paribus. Consumers do not perform with the expertness of a purchasing agent who specializes in buying a few articles for a large enterprise. But this does not demonstrate that consumers’ performance is suboptimal, given their preferences. [SeeConsumer Sovereignty.]

Closely related to retail distribution cost and performance is the degree of excess capacity. One observes underutilized space and personnel at some hours, days, or seasons, but at other times there are crowded stores and slow service. Despite some planned variations in number of employees, cost per unit of sales usually falls sharply when stores are crowded and rises when they are not. But quality of service moves in the opposite direction so that neither the recorded costs nor the “capacity” for service are fully comparable between the two types of occasions. Stores have had but little success with inducements to shop during slack hours or days. Clearly, consumers will accept inferior retailing service rather than change when possible their times of shopping sufficiently to even out the quality of service and make fuller use of the more fixed inputs in store operation.

What emerges is a picture of retailing as monopolistically competitive, in part because of differences in retailers’ location and combination of service, variety of goods offered, and hours of service. Equally important are differences in consumers’ preferences as to combination of service and price and in outlay of time and other costs they are willing to incur in order to identify the preferred combination. Consequently, each seller has a small amount of “built-in” monopoly. No alternative arrangement could bring perfect competition, nor would consumers’ welfare necessarily be improved thereby—except by some means of lessening the cost of valid information to them (Chamberlin [1933] 1950, pp. 213, 214; Lewis 1949, pp. 150-156).

The competitive character of the scene just portrayed rests on the autonomy of each shop, but it could be quite different where chain organizations do business at hundreds or even thousands of local shopping points. In the United States the largest two firms (chain store) accounted for 42 per cent of food sales, on the average, in 133 cities in 1958, and the largest four accounted for 58 per cent (Mueller & Garoian 1961, p. 9). Introduce the additional fact that some of these chains meet each other, but also one or more other chains and numerous independents in each of the various metropolitan areas, and the potentiality of reduced competition, at least in the form of low margins, is amplified. Thus far, such developments do not appear to have lessened price competition or to have increased profit rates. Restraining forces on monopoly include the difficulties of “agreeing” on the margins for each of hundreds of articles, the effectiveness of nonprice competition in shifting consumers’ custom, and the limited advantage of large chains over smaller ones and even over independents who have integrated themselves into wholesaling.

Effects on monopoly tendencies in supplying industries. A final phase of evaluating the performance of the distributive trades is whether they lessen or augment monopoly in the supplying industries. One purpose of manufacturers’sales programs for most consumer goods is to limit the retailer to physical handling and order taking. This is achieved to varying degrees for “convenience goods” bought frequently in small amounts, and it has occurred fully for cigarettes sold by dispensing machines. For “specialty goods,” or those bought infrequently, of high unit value and beyond the consumers’ capacity to judge by inspection, the manufacturer frequently makes the retailer of a brand de facto his exclusive agent (in a submarket), and the retailer builds his enterprise around his supplier’s product line (e.g., Pashigian 1961, pp. 11-51). There may be de facto “full-line forcing,” which compels retailers to pass back to the manufacturer any monopoly gains that arise from consumers’ preferences for the supplier’s goods (Burstein 1960).

For many goods, however, differentiation sets in motion dynamic counterdevelopments that pave the way for varying degrees of entry by large distributive enterprises into the supplying industries. For new goods, and these have become a substantial portion of consumers’ purchases in advanced countries, the techniques of persuading consumers to buy also inform them about the functional properties of a good and about its added reliability as quality is improved. At some point, consumers become more willing to break away from the manufacturer-retailer channel on which they had come to rely and to buy essentially the same product with a little-known label if offered at a substantial price saving. The firms in the best position to start this process of entry by an unknown, usually termed “private,” brand are the mass distributors (Heflebower 1957, pp. 278-285). They already have numerous retail outlets and a staff to purchase on a specification basis. If they are unable to buy a good that has reached this stage in the dynamic process, or more standard goods, at a very narrow small margin above manufacturing (not total) cost, they have the ability to overcome the entry barriers to manufacturing (Adelman 1959, pp. 248-274; Emmet & Jeuck 1950, pp. 374-470). Whether gains from such steps are retained for long or are passed on to consumers depends on the extent of retail price competition, which in the United States has been generally effective. But the processes just portrayed have not evolved for automobiles, tobacco items, or most proprietary drugs—for reasons that have not been studied thoroughly.

Efficiency in trade and economic development. Internal trade is more highly developed and more responsive to innovative influences in the growing, advanced countries than in those at an earlier stage of development. With regard to the consumer goods entering the markets of the latter, most evidence indicates that trade takes a much larger share of the retail price than in advanced countries. But there is debate as to whether this represents comparative inefficiency or the small volume, expensive transport, and slow turnover for goods, and the limited mobility of consumers, rather than monopoly. In very low income economies most distribution (except wholesaling of imported goods) is a form of self-employment.

There can be little debate about trade as a precondition to transfer from production for use to production for sale and the accompanying growth of efficiency. Availability of manufactured goods has a demonstration effect that stimulates production for sale or work for money wages. But during transition, the development of the efficient size of outlet and rapid turnover, with lower margins, comes only slowly indigenously. Speeding a reorganization of distribution often would do more to augment the real income of urban consumers than would probable improvements in commodity production. Where outside entrepreneurship and capital have been discouraged, distributive efficiency has lagged and there, as in some Western countries, the optimal distribution of resource use among commodity production, transportation, and internal trade has been slow in coming.

R. B. Heflebower

BIBLIOGRAPHY

Adelman, Morris A. 1959 A & P; A Study in Price-Cost Behavior and Public Policy. Cambridge, Mass.: Harvard Univ. Press.

Barger, Harold 1955 Distribution’s Place in the American Economy Since 1869. Princeton Univ. Press.

Burstein, Meyer L. 1960 A Theory of Full-line Forcing. Northwestern University Law Review 55:62-95.

Chamberlin, Edward H. (1933) 1950 The Theory of Monopolistic Competition. 6th ed. Cambridge, Mass.: Harvard Univ. Press.

Cox, Reavis; Goodman, Charles S.; and Fichandler, Thomas C. 1965 Distribution in a High Level Economy. Englewood Cliffs, N.J.: Prentice-Hall.

Earle, Wendell; and Sheehan, John 1966 Operating Results of Food Chains, 1965-1966. Unpublished manuscript, Cornell Univ.

Emmet, Boris; and Jeuck, John E. 1950 Catalogs and Counters: A History of Sears, Roebuck and Company. Univ. of Chicago Press.

Goldman, Marshall I. 1963 Soviet Marketing: Distribution in a Controlled Economy. New York: Free Press.

Hall, Margaret; Knapp, John; and Winston, Christopher 1961 Distribution in Great Britain and North America: A Study in Structure and Productivity. Oxford Univ. Press.

Heflebower, Richard B. 1957 Mass Distribution: A Phase of Bilateral Oligopoly or of Competition? American Economic Review 47, no. 2:274-285.

Holdren, Bob R. 1960 The Structure of a Retail Market and the Market Behavior of Retail Units. Englewood Cliffs, N.J.: Prentice-Hall.

Jefferys, James B.; and Knee, Derek 1962 Retailing in Europe: Present Structure and Future Trends. New York: St. Martins; London: Macmillan.

Lewis, W. Arthur 1949 Overhead Costs: Some Essays in Economic Analysis. London: Allen & Unwin.

Mueller, Willard F.; and Garoian, Leon 1961 Changes in Market Structure of Grocery Retailing. Madison: Univ. of Wisconsin Press.

Pashigian, B. Peter 1961 The Distribution of Automobiles: An Economic Analysis of the Franchise System. Englewood Cliffs, N.J.: Prentice-Hall.

Smith, Henry (1937) 1948 Retail Distribution: A Critical Analysis. 2d ed. Oxford Univ. Press.

Stigler, George J. 1961 The Economics of Information. Journal of Political Economy 69:213-225.

Twentieth Century Fund, Committee on Distribution 1939 Does Distribution Cost Too Much? A Review of the Costs Involved in Current Marketing Methods and a Program for Improvement, by Paul W. Stewart and J. Frederic Dewhurst. New York: The Fund.

United Nations 1963 Statistical Yearbook, 1962. New York: United Nations.

U.S. Bureau of the Census 1957 1954 Census of Business. Volume 1: Retail Trade. Washington: Government Printing Office. → See especially Table 3A.

U.S. Office OF Price Administration 1943 Food and Food Products. United States, Federal Register 8, no. 135:9388-9417.

Yearbook of National Accounts Statistics. → Published since 1957 by the United Nations. See especially the 1962 volume.