Every time a plane, train or truck ships a merchandise good across a border, it gets counted, by value and quantity. Individual shipments are recorded on bills of lading, and governments publish their trade statistics on a monthly basis. The trade statistics published by TDM are an aggregation of all those shipments grouped by commodity code and official government description (and not a list of specific bills of lading with company or brand names), organized according to the World Customs Organization’s Harmonized Standard (HS) codes.