Key points are not available for this paper at this time.
This note describes the construction and provision of an Internet database providing private and public sector union membership, coverage, and density estimates compiled from the Current Population Survey (CPS). 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. The database will be updated annually and can be accessed at http://www.unionstats.com/ .
Hirsch et al. (2003) studied this question.