According to the Public Religion Research Institute, 2011 was the first year, in their measuring anyway, in which supporting gay marriage was not a minority position among Americans: As of May, 51 percent were in favor, 43 percent were opposed. Given that it was an extremely big deal when Ellen DeGeneres came out and that was, like, 15 years ago, I don’t think you require particularly advanced math to see where we’ll be in another 15 years.
Meanwhile, a newly released poll breaks down the numbers by religion. The group that most strongly supported gay marriage did so 76 to 20, with nearly a majority—44 percent—saying they strongly favor it. Hint: This group was not “unaffiliated.” Unaffiliated had the second-strongest support of all the religious groups.
Beyond Secular vs. Religious: Religious Divides in Support for Same-Sex Marriage [Public Religion Research Institute]