28 Percent

Andrew Koppelman notes how far we've come as a country:

With Illinois’s passage of the civil unions bill, more than a quarter of the population of the United States – to be precise, a bit over 28% - now lives in a jurisdiction that recognizes same-sex marriage or its functional equivalent. It is only a bit over a decade since the Vermont Supreme Court ruled on December 20, 1999 that same-sex couples have the right to all the same rights and benefits as opposite-sex spouses. The same-sex marriage movement continues to be one of the most rapidly successful movements in American history.