A report by the U.S. Department of Labor's Bureau of Labor Statistics has found that 12 percent of employed wage and salary workers were union members in 2006, down from 12. 5 percent in 2005.

In all, unions counted 15.4 million workers among membership - a drop of 326,000 from the previous year. Union membership has been on the decline from 20.1 percent in 1983.

Union membership among government workers was at 36.2 percent, while private sector unions were at 7.4 percent.

In 2006, the union membership rate was higher for men - 13.0 percent - than for women - 10.9 percent. The gap between their rates has narrowed since 1983, when the rate for men was about 10 percentage points higher than the rate for women. The change occurred because the union membership rate for men declined more rapidly than the rate for women over that period.

In 2006, full-time wage and salary workers who were union members had median usual weekly earnings of $833, compared with a median of $642 for wage and salary workers who were not represented by unions.