Seems the creators of this data set were surprised to see how much change occurred in states where gay rights were popular in the 90s.
"In 1995, support for gay marriage exceeded 30% in only six states: New York, Rhode Island, Connecticut, Massachusetts, California, and Vermont. In these states, support for gay marriage has increased by an average of almost 20 percentage points. In contrast, support has increased by less than 10 percentage points in the six states that in 1995 were most anti-gay-marriage--Utah, Oklahoma, Alabama, Mississippi, Arkansas, and Idaho."
What's even more telling to me is that if you look closely, Utah has actually gone backwards. You'll have to click on the image to enlarge it, then look at the bottom. No surprise that Utah is the state were same-sex marriage has the least support but check it out more closely. The trend in Utah has seen a reduction in the amount of support of same-sex marriage. We see the change in the chart as represented by a blue triangle for the earliest percentage, then a grey square for 2003-04 and the a red circle for 2008-09. Utah's percentage of support in 2009 is almost as low as it was in 1994-5 and significantly less than in 2004. In fact, its the only state in the union with this backwards trend.
The article goes on to discuss the reasons behind the trend and the consensus is that in states were gay rights are more popular, more gays come out thus increasing the average number of gays a person knows and as this number increases, so does support for same-sex marriage. What it comes down to is the idea that as you know more people who are gay the more you realize that they're just people. And that they should have the same rights as you. Also, those states tend to be more liberal and get the liberal slant on the topic while the states were support is lower tend to be conservative and get the conservative slant on the topic.
20 states currently show 40%+ support for same-sex marriage. Only 5 have 25% or less. Interestingly, the authors assume that 50% is the tipping point and only 6 states have reached that level. NOT included in that are New Hampshire and Maine. Iowa has less than 40% support. New York, Rhode Island and California are at or above 50%. It's time to push hard in New York and Rhode Island and to push back against the tide in California.
Texas is just shy of 30% explicit support. We have a ways to go. But hey! At least we're not Utah.