The Union Membership and Coverage Database, available at www.unionstats.com, is an Internet data resource providing private and public sector labor union membership, coverage, and density estimates compiled from the monthly household Current Population Survey (CPS) using BLS methods. Economy-wide estimates are provided beginning in 1973; estimates by state, detailed industry, and detailed occupation begin in 1983; and estimates by metropolitan area begin in 1986.

This database provides time-consistent national and state-level estimates of union density for 1964 forward. Two sources of data are combined to produce these estimates, the Current Population Survey (cps), a monthly survey of U.S. households, and the discontinued bls publication Directory of National Unions and Employee Associations, based on data reported by labor unions to the government.

The union density measure represents the percentage of nonagricultural wage and salary employees who are union members, including employees in the public sector. A database available for years since 1977, based exclusively on the cps, provides a measure of union coverage density, representing the percentage of nonagricultural wage and salary workers covered by a collective bargaining agreement. The databases will be updated annually and distributed freely via the Internet.