Well, I'll offer my perspective from many years ago, although I'm sure a lot of it depends on the particular class and professor. I went to West Point, and nearly all classes were curved, at least after your basic plebe requirements (in which the grading seemed to be more by the book).
I spent a semester at the Naval Academy as an exchange cadet. First exam we got back in Electrical Engineering (Cables) the professor told the class that the class average was a 45.
Well, normally if this happened at WP, the prof would then go on to say something like say a 40-50 was a C, a 50-70 was a B, and above a 70 was an A. I raised my hand and asked what that meant. The professor replied "Means most of you failed!"
Incidentally, I worked my rear end off in that class, and barely, barely pulled an 80 (which was the lowest cutoff for a B and was the only one, and the highest grade, in my section). Spent more time on that class than my other 5 classes put together, all of which I got A's in easily. I went back to WP second semester, and got an A+ in Electrical Engineering without ever cracking the book.
So I guess, at least 20 years ago, it definitely depended!