U.S. Imports by TSUSA, HS, SITC, 1972-2001

This paper describes the updating of the NBER trade dataset, which now provides U.S.
import and export values to the year 2001, disaggregated by Harmonized System (HS), Standard International Trade Classification (SITC), and the U.S. Standard Industrial Classification (SIC) categories. In addition, U.S. tariff data at the HS level have been added for the years 1989-2001. Earlier CD-ROMs distributed by the NBER described data on U.S. imports and exports from 1972-1994, and these values have been slightly modified for 1989-1994 and then updated to 2001. Together with the earlier data, there are now 30 years of disaggregate U.S. trade data available to researchers.

https://cid.econ.ucdavis.edu/usixd/wp5515d.html