Atheism increases as people become more educated. Once they are enlightened by knowledge, they can see that the myth of a being in the sky who controls the world is hogwash.

Ask yourself, what do atheists have to be afraid of? Why should they need to be afraid? This is a very hate-filled world, and when someone's beliefs are threatened, they can get very aggressive. I've seen some very scary Christian rhetoric lately, so no, I don't tell people I'm an atheist. I tell them I'm agnostic. That way, they have hope they can "save" me and it keeps them off my back for awhile.