According to Gallup, 64% of Americans support marriage equality, with opposition at 34%. Even Republicans have plurality support for the position that the law should support marriages between same-sex couples.
To put it succinctly, Gallup says:
Though the Supreme Court has settled the legality of same-sex marriage, a third of Americans are opposed to it.
But support for gay marriage has gradually increased over the past two decades, reaching majority support with new groups, as it did with senior citizens in 2016 and Protestants this year. Republicans' support for gay marriage is also at a new high and could trend toward majority support in the near future.It is worth noting that nearly two years after Obergefell legalize same-sex marriage that a full third of respondents think it should be illegal.
However it is pretty awesome to see the trend; hopefully it will remain monotonically increasing from now on!