I think it's very close to 0%. There's just not much correlation. Knowing a lot about math or history or whatever 'book smart' type stuff doesn't help you in the game of hockey when you're on the ice thinking quick. It's a game that you either understand how to succeed at or you don't.
A good player example here is Jaden Schwartz. Very high hockey IQ, great all-around player. Does everything right. But apparently he's real-life dumb lol, and his teammates have said as much. Someone (I think maybe Burnside or LeBrun? I forget) actually wrote an article on him and touched on this subject. His teammates love him but were giving quotes and laughing about some of the things he asks them and they're just like "...are you serious?" For example, this was included in the article, he asked if Billy Joel used to play for the Rangers when they were at MSG.