The HS nomenclature is revised every five years. The last revision was in 2002 and in 1996 before that. Clearly, these two revisions have resulted in slightly different categories, descriptions and classifications. For this reason the WCO provides tables correlating the different versions of the Harmonized System with each other. To see these correlations, go to the World Customs Organization’s website.
For frequently asked questions about the Harmonized System, visit this link.