The official website of the North American Industry Classification System provides a list of codes by industry type. Within each industry type, there are sub-groups with each specific industry having its own reference number, up to a maximum of six digits.
The site allows users to search by NAICS code or keyword, and also displays the number of US businesses within each industry sector. Federal statistical agencies use these codes for the collection, analysis and publication of statistical data related to the business economy of the United States. The system was adopted in 1997 and replaced the Standard Industrial Classification system that used a divisional structure for classifying industries.