In my experience it depends on the part of the state. In the northwest there are more blacks, though there's still a good percentage of color-phase bears.

Down here in the southwestern part of the state color-phase bears are more common. Ingwe's guess of 60/40 is as good as any.

Chocolate-brown is the most common variation, but once in a while you'll see a "cinnamon" (light brown) or even a blond bear. The blond bears tend to die young due to lead-poisoning. A local friend got one a few years ago around here, a young bear.

I've seen some big color-phase bears in wilderness areas. A buddy and I got onto a big cinnamon bear just before sunset one year in the Bob Marshall. It was my shot and I passed, partly because in the dim light I couldn't be sure it wasn't a grizzly. My buddy was sure it was a black bear, but he wasn't willing to pay the 10-grand fine for me if it did turn out to be a griz.

On that particular hunt half the bears we saw were grizzlies, and the difference isn't always obvious. One of the top bear biologists in the world (Charles Jonkel of the U. of Montana) often said that he'd run into bears that he couldn't be sure about unless he caught them in a trap.

The prettiest color-phase bear I've ever seen up in northwestern Montana, too. It had a chocolate body but brick red legs and ears. It wasn't huge, maybe a six-footer, but it was too far to get to before dark and I never saw it again.

“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.”
John Steinbeck