Full Idea
Since the first recorded religion (in Iraq 60,000 years ago) it is estimated that mankind has produced in the order of one hundred thousand religions.
Gist of Idea
It is estimated that mankind has produced 100,000 religions
Source
Edmund O. Wilson (On Human Nature [1978], Ch.8)
Book Reference
Wilson,Edward O.: 'On Human Nature' [Penguin 1995], p.169
A Reaction
If asked to guess the number, I would probably have said '200'! This staggering figure seems to argue both ways - it suggest a certain arbitrariness in the details of religions, but an extremely intense drive to have some sort of religious belief.