Donna Leinwand Leger

USA TODAY

About 170 years from now, women worldwide will earn as much as men and account for half the world's bosses.

That's how long it will take to achieve economic parity between the sexes, according to the World Economic Forum's Global Gender Gap Report, an annual study made public Tuesday that measures the relative gaps between women and men in education, health, economic opportunity and political power in 144 countries.

Even as more women than ever attend universities, the report finds progress toward gender parity in other areas has slowed dramatically. In last year's report, the forum predicted women would hit economic parity with men in 118 years. In this year's report, the target date has jumped 53 years from 2133 to 2186.

And highly industrialized nations can't blame the worldwide gender imbalance on poor or developing nations. While Nordic nations – Iceland, Finland, Norway and Sweden – claim the top four spots on the global ranking for gender equity, the African nation Rwanda ranks 5th and Nicaragua displaced Switzerland for 10th place. The index ranks countries on their gender gaps, not their development level.

The United States failed to crack the top 25, ranking a dismal 45th place, a 17-spot slide from last year.

Behind the U.S. ranking is a study in contrasts. The U.S. earns a No. 1 ranking for educational equality –with equal numbers of men and women enrolled in primary education and more women than men enrolled in higher education – but 73rd in political empowerment, 62nd in health and survival, and 26th in economic participation and opportunity. Women are severely underrepresented on the boards of publicly traded companies, which are 81% male.

Glass ceiling: Women hold only one of five board positions

Rwanda broke into the top 10 with big improvements for women in economic participation and opportunity. The country also has the highest share of female parliamentarians in world at 64%.

Where a woman lives determines how long she'll have to wait for social, political and economic parity. Western Europe shows the most promise. Those countries have closed 75% of their gender gap and could close their economic gaps by the time a girl born today hits middle age.

The worst prospects for women reside in the Middle East and North Africa, the study found. There, only Israel cracks the global top 50, ranking 49th. The study estimates it will take more than three centuries for countries in that region to forge economic equality between men and women.

But Saadia Zahidi, head of education, gender and work at the World Economic Forum, says countries at the bottom of the list can alter their fate. The rankings, she said, reflect the current conditions and "should serve as a call to action for policymakers and other stakeholders to double down on efforts to accelerate gender equality."

Driving the growing gap is economic disadvantage. The study found women around the world on average earn just over half of what men earn, fill fewer executive offices and don't have as many opportunities in the workforce. The report predicts the economic lot for women will get worse before it gets better as technology displaces some jobs in developing nations.

Facebook Chief Operating Officer Sheryl Sandberg, citing the report in a Facebook post on Tuesday, said women remain an "under-utilized business resource," particularly in technology fields.

"In today's world, women need tech and tech needs women—but the number of women pursuing degrees in computer science is dropping and women are 25% less likely to have Internet access than men," Sandberg wrote. "This means women often lack the resources and access that will set them up for success."

Political power also remains stubbornly low for women, despite much progress since the forum began measuring political participation in 2006.

Education and health remain bright spots for women. In education, women lag just 5% behind men, and in health, just 4% as life expectancy rates rise.