Import data before 1974 do not exist on a transaction price valuation basis. Census data concordances link the 1980-92 trade figures into time series that are as consistent as possible. Data for 1970-79 are not linked and are from published sources. Import data before 1974 do not exist on a transaction price valuation basis. 1991 imports include revisions for passenger cars, trucks, petroleum, and petroleum products not included elsewhere.
Data are subject to revisions.
Data reflect all revisions through June 1994. Data for 1983-88 are estimated, based on the Harmonized System of commodity classification.