NEXT week, America could elect its first female president. Around the world, women rarely get the top job. The World Economic Forum, a think-tank, has tallied data on women in power in 144 countries for the past 50 years. During that time period, just under two-fifths of the countries surveyed had a female head of state or government at some point for at least a year (excluding monarchs). In half of those countries, the total time served by female leaders falls short of five years, a common length of a single full term in office.

Like Hillary Clinton, who is the wife of a former American president, many female heads of state have hailed from political dynasties. At least a dozen are the wives or daughters of former presidents or prime ministers. They include the two women who, between them, have held the prime minister’s post in Bangladesh for 23 of the past 50 years—the longest any country has had women at the helm.