(CBSNews) -- If you're reading this sentence, you may never live to see the day when women earn as much as men.

At the current rate of change, it will take roughly two centuries for women around the globe to achieve "economic gender parity," including in the workplace, the World Economic Forum said Tuesday in a new report. Although the income gap between the sexes narrowed this year, women continue to earn only 51 percent as much as men.

The upshot: Women are making progress, but on a number of key measures it is achingly slow. In assessing progress in terms of economic opportunity, political empowerment, educational attainment, and health and survival, the world has closed 68 percent of its gender gap, concludes the group, known best for staging the annual conclave in Davos, Switzerland, that gathers many of the world's top movers and shakers.

Still, the World Economic Forum estimates it will take 108 years for there to be equal representation between male and female executives in the boardroom.

"Stagnation in the proportion of women in the workplace and women's declining representation in politics, coupled with greater inequality in access to health and education, offset improvements in wage equality and the number of women in professional positions," the group said in a news release.

Most equal countries

Iceland remains the nation with the most level playing field between women and men, a ranking it's held for 10 straight years. Other countries ranking near the top for gender equality include Norway and Sweden, landing at No. 2 and No. 3, respectively, on the World Economic Forum's list.

But it's not only egalitarian-mind Nordic countries that promote gender parity. Nicaragua overtook Rwanda to place fifth in this year's ranking, while the newest entrant in the forum's top 10 is Namibia.

The U.S. moved down two spots to No. 51, with modest improvements in economic opportunity offset by a decline in gender parity in government leadership.

Closing the gender gap isn't only about fairness -- it's also about boosting countries' economic productivity and enhancing global political stability, according to the World Economic Forum.

"The economies that will succeed in the fourth industrial revolution will be those that are best able to harness all their available talent," Klaus Schwab, the group's founder and executive chairman, said in a statement. "Proactive measures that support gender parity and social inclusion and address historical imbalances are therefore essential for the health of the global economy as well as for the good of society as a whole."