International Women's Day is coming up in a couple of weeks, so it's worth looking at an issue that's extremely important both for women's rights and welfare as well as for any country's overall economic health: female labor force participation.

That's a jargony way of measuring the percentage of women ages 15 and up who are employed. The higher this number, the better for women (economic self-sufficiency, or at least the potential to be economically self-sufficient, is closely linked with all sorts of other basic rights) and the better for countries. Any country where it's hard for women to work, whether because they're pressured to stay home or because educational attainment is tougher or just because of straight-up discrimination, is effectively suppressing half of its economic potential. That makes everybody poorer and worse off.

So this number is important. It's also awfully low in big parts of the world. Up top, I've mapped out the most recent data from the World Bank's World Development Indicators on female labor force participation rates. In red countries, less than half of over-14 women are working. In blue countries, it's more than half. In purple countries, about half work.

A couple of caveats here. The World Bank sets the working age as 15 or above, but obviously lots of high school- or college-aged girls and women don't work because they're getting an education. This is especially true in wealthier countries where education rates are higher, for example in Europe, and artificially depresses the participation rates. The second caveat is that some countries have high unemployment for men and women, so low female participation rates could partially reflect high unemployment across the board.

Still, in broad terms, this is a useful snapshot of where women are and are not working. Here are a few observations.

Women work least frequently in the Middle East and broader Muslim world. This is not uniformly true across all Muslim-majority countries, but it's tough to miss the trend. Partly this reflects rising unemployment in these countries, but with fewer than one in four women at work in many of them, it clearly goes beyond that. It's not easy to talk about the effects of cultural norms on economic output, especially in terms that can sound like value judgments. But the simple fact is that in countries where women are widely and at times systemically told that they cannot choose their own clothing, or have less than equal political or legal rights, it's hardly shocking that they would not be invited into the work force as equals. That holds these countries back from realizing their fuller economic potential.

Japan and South Korea have unusually low female participation. This also gets at cultural norms, though they're somewhat different. Japan and South Korea are still getting over legacies of rigidly proscribed, Confucian-linked gender norms, which make it tougher for women to be perceived as equals in the workplace. Revolutionary China worked very hard to overturn these norms, to partial but substantial success, which you can also see here. And there are non-Confucian countries with histories of gender inequality that see a similar outcome, for example in Italy.

Why is Europe so purple? Partially, as mentioned before, this is about Europeans generally entering the work force later than in other countries, as well as high unemployment from the Euro crisis. But there's a bit more here as well. Women's rights are obviously quite good here, but many of these countries are facing demographic crises as birth rates decline. A number of European governments, most especially France's, are instituting all sorts of policies to encourage women to have more babies. That's a long-term economic strategy, but it also has a short-term downside, which you can see here.

Socialist states are actually pretty good at this. The Cold War-era spread of socialist governments, many of them deeply authoritarian, obviously was not all good. But one positive element was the movement's ideological emphasis on bringing women into the workforce. You can see that legacy in a lot of otherwise moribund socialist or post-socialist economies, particularly in southeast Asia.

India's rise is being held back. Akshat Rathi, writing at Quartz, is not the first person to make this case, but he makes it well. “To a certain extent, men control women’s lives. And women have internalised this as the norm," Preet Rustagi, joint director of Institute for Human Development in Delhi, tells Rathi. "In such situations, the little work they do is the result of compulsion, such as when the household income is not enough, rather than choice.”

That's just the tip of the iceberg, of course, for possible lessons from this data. There are the unusually high participation rates in East Africa, the low participation rate in South Africa, and the interesting variations within Latin America. We expect to explore these stories and more around International Women's Day, which is March 8, so do check back.

Max Fisher is the Post's foreign affairs blogger. He has a master's degree in security studies from Johns Hopkins University. Sign up for his daily newsletter here.