Dept of Labor, Bureau of Labor Statistics

Highlights:

16.9M Workers in 2009 had union represenation

There are more public sector (gov employees) than private sector union members.

New York has more union members; South Carolina has the fewest

Among full time salary workers, union members had median usual weekly earnings of $908, while those who were not represented by unions had median weekly earnings of $710.

By age, the union membership rate was highest among workers 55 to 64 years old (16.6 percent). The lowest union membership rate occurred among those ages 16 to 24 (4.7 percent).