I've highlighted some of their data previously, here and here, where they did exhaustive studies of the views on a variety of GLBT equality issues, by state and by age. The trend is clear.
And support for same-sex marriage has increased in all states, even in relatively conservative places like Wyoming and Kentucky. Only Utah is still below where national support stood in 1996....Today's column updates their paper from last year, Upcoming in Gay Rights in the States: Public Opinion and Policy Responsiveness Jeffrey R. Lax and Justin H. Phillips Columbia Univ. American Political Science Review, Vol. 103 (3), 2009, which provided these graphs. Click for a closer view.
This trend will continue. Nationally, a majority of people under age 30 support same-sex marriage. And this is not because of overwhelming majorities found in more liberal states that skew the national picture: our research shows that a majority of young people in almost every state support it. As new voters come of age, and as their older counterparts exit the voting pool, it’s likely that support will increase, pushing more states over the halfway mark.