Today the Bureau of Labor Statistics released new data on union membership for 2013. The data show women’s union membership held steady in 2013 after dropping sharply the year before – and that’s a relief for women seeking better wages and equal pay.

NWLC analysis reveals that the wage gap among union members is half the size of the wage gap among non-union workers and female union members earn over $200 per week more than women who are not represented by unions—an increase that represents a larger union premium than men receive.

This release is especially timely. Earlier this week the Supreme Court heard arguments in a case that challenges the right of low-wage workers, overwhelmingly women, who provide home care services under Illinois’ Medicaid program—and potentially the right of all public employees—to be represented by unions. Today’s data make it clear that this case has high stakes for working women and men.

Here are all the details:

The wage gap among union members is half the size the of the wage gap among non-union workers.

Among union members, women working full time are typically paid 90.6 percent of what their male counterparts are paid – a wage gap of 9.4 cents.

Among non-union workers, women working full time are typically paid 81.3 percent of what their male counterparts are paid – a wage gap of 18.7 cents.

The wage gap among union members shrunk by 2.6 cents between 2013 and 2012 (to 9.4 cents from 12.0 cents) – for non-union workers it was virtually unchanged (18.7 cents in 2013, down 0.5 cents from 19.2 cents in 2012).

Women’s union premium is 1.4 times as large as men’s.

Union members typically make more per week than non-union workers – but the bonus is larger for women.

Female union members who work full time typically make $898 per week – $222 more than female non-union workers who typically make $676 per week.

Male union members who work full time typically make $991 per week – $160 more than male non-union workers who typically make $831 per week.

The rate of union membership remained flat, but public sector union membership declined.

The number of union members increased between 2012 and 2013 but the rate of union membership was unchanged at 11.3 percent.

The percentage of employed women who were union members remained constant at 10.5 percent, while the rate for men dropped by a tenth of a percentage point to 11.9 percent.

The number of public sector union members declined between 2012 and 2013 and the rate declined to 35.3 percent in 2013 from 35.9 percent in 2012. The largest decline was among local government workers, down to 40.8 percent in 2013 from 41.7 percent in 2012.

Technical note: Data and trends on union representation (workers represented by unions include both workers who are union members as well as those who do are not members but whose jobs are covered by a union contract) are not reported here but are similar to those for union membership. Wage gaps in this analysis are calculated based on median weekly earnings. These data differ slightly from the often-used measure of median annual earnings for full-time, year-round workers. Using that measure, the typical woman makes 77 percent of what the typical man makes. See National Women’s Law Center, The Wage Gap is Stagnant in the Last Decade (September 2013) available at https://www.nwlc.org/resource/wage-gap-stagnant-last-decade.