The U.S. Government agency responsible for collecting and publishing the bulk of industry statistics is the U.S. Census Bureau, a division of the Commerce Department. Reports based on these statistics are organized by NAICS, the North American Industry Classification System. [http://www.census.gov/ eos/www/naics/] You can also use the Free NAICS Look Up from the NAICS Association.
Every five years (years ending in 2 and 7), a comprehensive Economic Census is conducted to gather details about economic activity by sector and by state, and, in most cases, for counties and cities as well. Start with Industry and Local Business Statistics followed by Industry Snapshots for a summary for industries in the 2-digit NAICS code at the national or state level. Then click on the Industry Statistics Portal link for more details.