Estimates of Union Density by State

This paper describes the construction of time-consistent national and state-level estimates of union density for the years 1964 through 2000. 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 more limited database, available for years since 1977 and 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