I'll throw my opinion out there on this subject. I hold an Associates degree in divinity which means I know enough to get me in a little trouble, but not enough to save the planet. (laughing) . Here's my take ..
I think that everybody believes in God. Now, stay with me for a minute. There are about 10% of the people who don't agree with the rest of us on who God really is. See, if the God of creation doesn't exist, then people become their own God. The number on atheist reads nine, sometimes 10% depending on your source. That figure isn't actually correct though, because when you talk to those people and dig in, you find that about half a are actually agnostic. Way off subject, sorry ..
People by nature don't do a very good job of managing things, so it's sad to say that some people have to rely on themselves as God. It also strips life of any meaning which sucks also.