The Standard Industrial Classification (SIC) code number was established in order to promote the comparability of statistics. The SIC code has been revised over the years and some code numbers have changed.
It is important to be careful when comparing data from different publishers and over a long period of time. Beginning with the 1997 Economic Census, the Census Bureau began using a new North American Industrial Classification System (NAICS) (pronounced "nakes") which is more closely aligned with international codes.
Many commercial publications have converted to NAICS, but some still use SIC codes.