Nate Silver writes at the New York Times:
By August, there will be about 585 million people living in countries or jurisdictions where same-sex marriage is legal. That is roughly double the 289 million people living in such places in August 2012. Still, that represents only about 8 percent of the global population. No country in Asia, which has well more than half the world’s people, has authorized same-sex marriage. Instead, it’s the New World that has taken the lead. Of the 585 million people living in jurisdictions where same-sex marriage will be legal by August, about 360 million are in the Americas.
Silver notes that with the addition of California, 30% of Americans will have access to same-sex marriage in their home states. By comparison, 23% of Europeans do.