The ratio of women’s to men’s median weekly full-time earnings declined from 82.5 cents on the dollar in 2014 to 81.1 cents on the dollar in 2015, according to new data released this week in advance of International Women’s Day on March 8 by the nonprofit Institute for Women’s Policy Research, a Washington, D.C.-based research organization. Women’s median weekly earnings for full-time work were $726 in 2015 compared with $895 for men, the study found . Controlling for inflation, women’s earnings increased by 0.9%, while men’s earnings increased by 2.6% since 2014.

“While we have many advancements to celebrate since the first International Women’s Day more than 100 years ago, the widening of the wage gap, even as women have higher levels of education than men, is a setback for women, their families, and the U.S. economy,” Heidi Hartmann, the organization’s president, said in a statement. Black women saw the smallest gains in weekly earnings among women, while black men were the only group to see no weekly wage growth at all. Black women’s real earnings increased by 0.5% last year over 2014, compared with 4.2% for Asian women, 3.2% for Hispanic women and 1.1% for white women.