Bureau of Labor Statistics Employment Hours & Earnings - search for data from past 10 years.
Plunkett Research publishes almanacs which offer business intelligence, industry trends, statistics, market research, sales leads & corporate profiles in your choice of formats and access plans. While some information is available free on their website, most reports are only available for with an annual subscription.
NAICS was adopted in 1997 to replace the Standard Industrial Classification System (SIC). This is the standard used by U.S. Federal agencies to classify businesses for the purpose of collecting and disseminating statistical data.
United Nations' classification system
Company and industry ratios are available at MSN Money website. Click on the "Investing" link and enter the ticker symbol or name of your company.
You can also compare your company to the industry ratios through the Reuters website. Search for your company by name or ticker symbol, then select the "Financials" tab.