Imports are shown according to country of origin and exports according to ultimate destination. When the final destination is not known the shipment is credited statistically to the country to which it is consigned. Accurate information on country of origin is difficult to obtain. Consequently, the directional breakdown of foreign trade is at best approximate.

Trade with Canada and the United Kingdom, particularly, is difficult to measure. Considerable U.S. merchandise normally moves to foreign destinations via Canada and some moves across Canada to destinations in the United States, notably from ports in Michigan to ports in New York. At times such movements have been counted as trade with Canada. Also, considerable Canadian trade with other countries moves through the United States. A good deal of United States merchandise has been consigned to the United Kingdom and reexported to other markets by the United Kingdom, as can be observed by the difference between general imports and retained imports in the United Kingdom's record of trade with the United States.

Special studies of U.S.-Canadian trade have been made from

time to time. In this connection, see the headnote to the table, p. 295 of Commerce Yearbook, vol. II, for 1931; and see MSCF, June and July 1898, pp. 2084–2089, where it is also noted (p. 2075) that "exports to Canada are incomplete prior to April 1, 1893, the date on which the law requiring exporters to clear their goods exported by railways went into effect." For an effort at adjusting the U.S. trade record for this deficiency and the similar lack of coverage in the report of trade with Mexico, see tables 2 and 3 of Matthew Simon's "The United States Balance of Payments, 1861-1900" published by the National Bureau of Economic Research in Studies in Income and Wealth, vol. 24, 1960. For a discussion of shortcomings in the U.S. record of trade with the United Kingdom in the early years of the Civil War, see the Treasury's report in 1864 to Congress, Statistics of the Foreign and Domestic Commerce of the United States, p. 37 ff. For certain periods, like the Civil War and the greenback era, partners' records of trade with the United States are more reliable than the U.S. record and in some ways more revealing of certain aspects of the trade.

For 1862-1879, exports of domestic merchandise are mixed gold and currency values. Imports and reexports, however, are specie values. The extent of the adjustment can be observed by comparing figures from series U 317 with those in series U 190.

Prior to 1873, trade figures for Canada are actually trade figures for all of British North America, a somewhat larger area than the Dominion of Canada. Asia includes the Philippines in all years and Turkey in Europe for 1926-1951. Oceania includes Hawaii prior to 1901. Europe includes the Soviet Republic in Asia since 1923 and Iceland in all years (Iceland was included with northern North America in Historical Statistics of the United States, 1789–1945). The source for these series for 1821-1881 is the Treasury Department, Bureau of Statistics, Monthly Summary of Commerce and Finance, hereafter abbreviated as MSCF.

U 317-334. Value of exports (including reexports) of U.S. merchandise, by country of destination, 1790–1970.

Source: 1790-1820, series U 317, see source for series U 190. 1790-1820, series U 318-334, U.S. Department of the Treasury, Bureau of Statistics, Statistical Tables Exhibiting the Commerce of the U.S. With European Countries 1790-1890, 1893, pp. xiii, xiv, xviii, and xix. 1821-1881, series U 317, MSCF, April 1898, p. 1632; series U 319, 1821-1872, MSCF, June 1898, p. 2091; 1873-1881, U.S. Department of Commerce and Labor, Statistical Abstract of the United States, 1907, p. 317; series U 320-322, MSCF, August 1901, pp. 618, 626–627, and 632-633; series U 324–328, MSCF, October 1896, pp. 718, 730-732, and 745-746; series U 329-332, MSCF, April 1898, pp. 1632, 1637, and 1638 (except for China, 1865-1881, Statistical Abstract, 1907, p. 350); series U 333–334, 1821-1864, MSCF, June 1896, pp. 1612, 1621, and 1622; 1865-1881, Statistical Abstract, 1907, pp. 366, 376 (data for total America and "other" series were obtained as residuals for 1821-1881); 1882-1946 and 1966-1970, the following editions of the Statistical Abstract:

ΝΑ

Not available. Z Less than $500,000 or less than $500,000. 1 Includes gold and silver prior to 1821. Beginning 1961, includes exports and imports of uranium, thorium, and related products; beginning 1968, includes silver ore and bullion.

2 Prior to 1864, domestic exports of silver included with gold.

3 Beginning 1968, silver ore and bullion included in merchandise exports and imports. 4 Figures which include estimates of civilian supplies shipped to occupied areas through U.S. Armed Forces and other relief agencies are as follows (in millions of dollars): 1944, 14,414; 1945, 10,530; 1946, 10,184; 1947, 15,338.

5 Does not add due to revisions not carried to detail.

• Figures for 6-month period July 1, 1915-Dec. 31, 1915, are as follows (in millions

of dollars): Series U 187, 1,905; series U 188, 1,239; series U 189, +667; series U 190, 1,853; series U 191, 1,820; series U 192, 33; series U 193, 913; series U 196, +940; series U 197, 24; series U 198, 307; series U 199, 29; and series U 200, 19.

7 Period beginning Oct. 1, 1842, and ending June 30, 1843.

8 Data shown under silver are for gold and silver.