Why are very intelligent people less likely to be religious?

This is just an observation I have made, but it seems like very intelligent people (particularly in the scientific community), are either atheist or agnostic. A survey conducted a few years ago at the Universities in America showed that over 60% of Psychologists were atheist, and well over 70% of biologists were atheist. Einstein was agnostic, Carl Sagan was agnostic, Bill Gates is atheist, Steve Jobs is atheist/agnostic, Watson and Crick, the discoverers of DNA, were atheist, Steven Hawking is atheist, Mark Twain was agnostic, Marie Curie was agnostic, Thomas Edison, the famous inventor was also atheist. It just blows my mind that all these smart people couldn't see God. What is going on here!?