Atheist Census: Numbers Matter. Be Counted.

If you don't believe in supernatural beings, sign it. From the FAQ: 

Atheist Census is a project to count and collect demographic information on the world’s atheists which aims to build a picture of the world’s atheists – where they are, their genders and ages, their education and religious (if any) background – and use that information to demonstrate the presence and importance of atheists in societies around the world.