Today the Bureau of Labor Statistics released new data on union membership for 2012. We did some number-crunching which shows that while unions are really important to women, their membership is dropping.

What’s going on with women and unions?

• Between 2011 and 2012 the number of union members dropped by 398,000. Women were less than half (46 percent) of union members in 2011 – but they accounted for 72 percent of the decline.

• Men are more likely than women to be members of unions. The gap between men’s and women’s union membership has narrowed over time. Last year it grew, for the first time since 2008, by 25 percent. Women’s rate of union membership (11.2 percent) was 1.2 percentage points lower than men’s (12.4 percent) in 2011. In 2012, women’s rate (10.5 percent) was 1.5 percentage points lower than men’s (12.0 percent).

Why does this matter?

• Union membership is critical for women’s wage equality. Among union members, the typical full-time woman worker has weekly earnings that are 88 percent of the typical man’s. Among workers not represented by unions, this figure is 81 percent.

Why is it happening?

• It’s likely that women’s concentration in public sector jobs (women comprised 57 percent of the public sector workforce in 2012) was a key factor in this union membership decline.

• The rate of union membership in the public sector workforce in 2012 was more than five times higher than in the private sector (35.9 percent as compared to 6.6 percent). Public sector workers comprise just over half (51 percent) of union members in 2011, but they accounted for 59 percent of the declines in union membership between 2011 and 2012.

A few wonky data details: BLS data on union membership include all employed wage and salary workers 16 and older. Figures are 2011 and 2012 annual averages. Data are not available broken down by gender and sector. Data on the wage gap for union members differ slightly from the often-used measure of median annual earnings for full-time, year-round workers. Using this figure, the typical woman makes 77 percent of what the typical man makes.

This post was originally posted at NWLC. Reprinted with Permission.

About the Author: Katherine Gallagher Robbins is a Senior Policy Analyst for Family Economic Security at the National Women’s Law Center where she examines how tax and budget policies influence the financial stability and security of low-income women and families.  Before joining the Center in 2010, Ms. Gallagher Robbins worked as an organizer for the California Public Interest Research Group at the University of California, San Diego. She is a Ph.D. candidate in Political Science at the University of Michigan, Ann Arbor, and a graduate of the College of William and Mary.