NEA = National Education Association 2,495,826 22%
Teamsters = International Brotherhood of Teamsters 1,400,700 12%
UFCW = United Food and Commercial Workers International Workers1,319,399 12%
SEIU = Service Employees International Union 1,321,790 12%
AFSCME = American Federation of State, County, and Municipal Employees 1,300,00 11%
LUNA = Labors International Union of North America 774,696 7%
IMAW = International Association of Machinist and Aerospace Workers 737,510 6%
IBEW = International Brotherhood of Electrical Workers 718,742 6%
American Federation of Teachers 686,518 6%
USA = United Steelworkers of America 636,927 6%

This list excludes the International Union 762,436