The following HTSA files are available back to 1989, the first year of publication of the Harmonized Tariff Schedule. Due to changes in software and formats, many of the early files do not contain all the graphics lines and header information as was originally printed. They do, however, contain the necessary information to look up duty rates that were in effect at the time. Electronic revisions were made available for interim periods between publication of Basic and Supplement versions, but are not included here. Thus, some changes may have occurred between the publications listed, but are always reflected in the following editions.