It's not that difficult to make quality guess as to these numbers - based on election results most of the time, Fox News Ratings, percentages of religious people in America (incidentally it applies to Canada or anywhere so I should not exclude the nutter there).

Subtract the non religious who vote conservative for entirely non religious views ratings such as their fiscal policy (although that may not make them any smarter!)

Add back percentages of Universities that almost entirely are left wing institutions (and their graduates), subtract the people who say they're Christian but who list only because they were born into a Christian family and don't really follow the teaching (ditto all other religious in name only folks)

Add in that 100 is deemed the mean IQ level which means half would be above that number and half would be below that number and 50% is a pretty reasonable guess. Indeed if the mean is 100 it means that half the people would be below 100. And that's the number I presented. University enrollment and the fat they overwhelmingly lean to the left/liberal side of the spectrum would indicate that more people in the above 100 camp are both university graduates, and thus tend more to the left liberal ideologies as do most of the professors. Which therefore means that more of the people below 100 are not. This was certainly what I experienced at University - with rare exception did I meet ultra right wing fanatics - one very nice Mormon fellow - he was intelligent enough to get into University but he did poorly in the classes I had with him - History where he was scraping by with C's and he was kicked out of the teaching program.

Of course there are smart people who have faith but as Dawkins noted that it takes a lot of brain gym and a willingness to shut one side of your brain off that uses reason to say "the heck with it I'll believe in the giant tooth ferry/tea pot in the sky for no valid reason whatsoever because a very weak book, the bible, passes as truth.

The entire religion is based on copying previous whack-job religions and it doesn't even make sense historically.

The God Who Wasn't There - 2 - Jesus Timeline - YouTube

Just compare the Jesus myth to the Oedipus, Romulus, Theseus myth stories of the time. They all follow a general pattern and granted people are brainwashed by their parents as soon as they can understand English but at some point you learn Santa isn't real.

The God Who Wasn't There - 3 - Raglan Hero Pattern - YouTube