The Pew Forum on Religion and Public Life has created a series of graphics shows how public opinion toward same-sex marriage has changed in Pew Research Center polls since 2001.
The graphs show how much opinion varies by generation, religious group, gender, race and political party since 2001.
On general attitudes same sex marriage:
In 2001, Americans opposed same-sex marriage by a 57% to 35% margin.
Today, the public is about evenly split, with 47% in favor and 43% opposed.
On generational change in attitude:
Younger generations express higher levels of support for same-sex marriage.
In 2012 Pew Research Center polling, Millennials are twice as likely as the Silent Generation to support same-sex marriage.
When attitudes are compared to religion preference:
Among people who are religiously unaffiliated, a solid majority have supported same-sex marriage since 2001...
and among Catholics and white mainline Protestants, roughly half now express support for same-sex marriage.
Support among white evangelical and black Protestants remains lower than among other groups.