We’ve reported here on the Bureau of Labor Statistics numbers that showed that the numbers of unionized Americans continued its historic and sharp decline throughout 2012. But now that the dust has settled a little, can you guess which union remains the largest in terms of membership in the U.S.? The Teamsters? How about the UAW? Or perhaps the SEIU?

If you guessed any of those, you’d be wrong. The union with the largest membership in 2012 according to recently filed LM-2 reports remains the National Education Association which counts 3.1 million educators as members. But even the NEA shrunk in 2012, losing more than 99,000 members.

Other big losers in terms of membership numbers (from 2011 to 2012) include:

  1. Teamsters – down 51,924 to 1.3 million (a 4 percent decrease)
  2. Service Employees International Union – down 44,960 to 1.9 million
  3. Laborers – 8,422 fewer members
  4. United Food and Commercial Workers – 13,102-member drop
  5. Machinists – lost 4,033 members

There were some increases though. The IBEW added 4,978 additional members in 2012. The UAW increased their membership in 2012 by 1,794 members to 382,513. The United Steelworkers also increased their membership in 2012 growing by 7,100 to 614,054 members.