Thanks for all the good stuff.
I'll definitely have to find your statistic by terrain type thread, it is exactly what I'm looking for.

I started on it a little by myself with Edi's excellent DB, but there's some site mask that don't correspond to anything in the terrain index.
The site gen mechanic seems strange, I've read the same mechanic on the other thread, though I asked again because those threads had arguments on the mechanic.
Playing on default 45% site gen, that should mean 55% of the lands have no sites at all, and 45% have 1-4 site. The breakdown seem to be:
55% Provinces have no site
45% of them having sites:
4% - 4 sites
9% - 3 sites
20% - 2 sites
67% - 1 site
My gut feeling is that they appear more often and the 2 sites show up more then 20%, though that's probably gambler's folly on my part. I'll have to test a 50% game with a rainbow pretender methodically.