WASHINGTON — Union membership dropped slightly in 2004, to 12.5 percent of all workers nationwide, the Bureau of Labor Statistics said. However, Minnesota experienced a slight increase in unionization.

New York is the most organized state, with one out of every four workers a union member. Other top states for union density include Hawaii (23.7 percent), Michigan (21.6), Alaska (20.1), New Jersey (19.8), Washington (19.3), Minnesota (17.5), Illinois (16.8) and California (16.5). North Carolina was last (2.7 percent). All those states, save New York and Minnesota, saw declines in the union share of the workforce. New York's share rose 0.7 percent, or 90,000 workers. Minnesota's rose 0.5 percent.

BLS said there were notable percentage drops in Alaska (-2.2 percent), Illinois (-1.1 percent, or 95,000 workers, to 905,000) and Missouri (-0.8 percent, or 48,000 workers, to 315,000). It also said unionists now are 7.9 percent of all private workers, but 36.4 percent of public workers.

Including independent unions such as the Carpenters and the National Education Association, unions had 15.5 million members. Almost precisely half live in just six states: California, New York, Michigan, Illinois, Pennsylvania, and Ohio, in that order.

The most-unionized occupations included local government workers (46.7 percent), federal workers (36.8 percent), state workers (34.2 percent), education (37.6 percent), utilities (28.4 percent) and transportation (24.6 percent).

Some of the categories overlap. The Fire Fighters, who would be counted in government workers, represent 85 percent of U.S. fire fighters.

Unionists still enjoy a significant wage gap over their non-union colleagues, BLS said. The average union worker makes $781 per week, while the average non-unionist makes $612. Overall, the average U.S. worker makes $638.

Subgroups had similar gaps.