A group for those without religion, as well as those who oppose it. Atheism and Agnosticism and Anti-theism.
Good news for American atheists. Stats taken in 2012 are saying that 60% of Americans describe themselves as "religious person". Another 30% as "not a religious person". 5% Are "A convinced atheists" and rest doesn't know response. This is quite a change because in 2005 there were 73% of "religious persons" in USA. That means that atheist situation in USA is becoming better year by year =)