The statistics in exhibit 20a reflect trade in goods on a balance of payments (BOP) basis while the statistics in exhibit 19 reflect trade in goods on a Census basis. Goods on a Census basis are adjusted by the U.S. Bureau of Economic Analysis to a BOP basis to align the data with the concepts and definitions used to prepare the international and national economic accounts.

To derive the seasonally adjusted statistics by geography for trade in goods on a BOP basis, these BOP adjustments are applied to the not seasonally adjusted data on trade in goods on a Census basis, and the BOP basis totals for the selected countries and world areas are then directly seasonally adjusted.