Women make up just over half the human population, and yet the overwhelming majority of policymakers and political leaders in the world's governments are men. In fact, there are just three countries on earth where women make up more than 50 percent of the national legislature, and only 21 countries (out of 193 UN member states) in which a woman is either head of state or head of government. What's more, no G7 country currently has an elected female leader. While some countries have introduced controversial gender quotas at various stages in the electoral process as a bid to increase female participation, there's lots of progress still to be made. Here's a look at the facts and figures.