TheSIC Manual was last revised in 1987; it provides the government-assigned (four-digit) numerical codes for identifying industries, businesses, and products. With the adoption of the North American Free Trade Agreement, the SIC is officially replaced by NAICS. However, some industry publications still provide data based on the SIC (Print copy is available in the Ready Reference. HF 1042 .A55 1987).
Data on the U.S. imports and exports of merchandise is based on the HTS. It provides a detailed tariff classification system covering more than 10,000 product categories.
HTS is available in the Library: CDROM 714; U.S. Documents ITC1.10:
The ISIC is the standard industrial classification of all economic activities. It is a (four-digit) classification system for statistics on economic activity (e.g. agriculture, manufacturing, retail and wholesale trade.)