I believe atheism, or at least a lack of religious belief is actually the most common thought
In the US particularly, we've been raised to be afraid (because of the vicious verbal and physical attacks of the religious groups) to say if we are atheistic or don't believe in god or the gospels. So, many people who don't believe, never speak up. This is the silent majority. More and more I realize that most of the people I know do not believe if religion, but just don't openly talk about it until they think they are around like-thinkers.