Hmmm. It's different with different universities and colleges. What can I say? It is also meaningless except with that university or college. And unusual system may need translation for external use, however.
A typical (not universal) grade scheme is 90, 80, 70, 60 for the minimum marks for A, B, C, and D respectively. However, grading is itself individualized so the grades often are awarded to meet those breaks. How well has the student mastered this material. "Near perfect" = 90-something. "Almost" yields 80 or so. Etc.
And numeric grades within a course are usually fractional. 3.8 is not as good as 4.1, but only by a little. For the transcript, though, they might be integers only or "half" scores: 3.5, sometimes with a max of 4.5. The overall will be a fractional GPA: 3.7 or 3.72, say.
Note that the grade distribution for a class is likely to be different for entry level (first year) courses and for later (upper division) ones. The less serious students have likely gone elsewhere. If the same "curve" applies then it is almost certainly unfair. A lower mean and a larger variance is likely for an entry level course, especially if it has many students.
I've taught courses at a top university where nearly every student earned and deserved 90 plus. They worked hard and made me work hard as well. I've also taught courses where students had been accustomed to be a bit lazy and were a bit shocked with their low grades. It was, fortunately, a convincing goad to get them to work harder.
Every group is different, not just every university. A group of 400 or so students might have something like a normal distribution of grades (honestly and fairly) but a group of 40 isn't likely to. It is too small. Probably skewed one way or the other as in the two examples above.
Note that large groups with many sections and lots of TAs need to take some precautions to assure that grades are fair across sections and TAs.
My advice is to make grading individualized but using a rubric. Consider every student to be different from every other with their own strengths and weaknesses.
And if you impose a grading scheme such that some student has to get low marks so that others can get higher marks (competitive grading) then IMO you are being unethical.
Your job is to teach them. I.e. set up the conditions for learning. It isn't primarily to grade them. You aren't the Hogwarts sorting hat.
At the end of a course, do an informal evaluation of your grades prior to filling out grading forms. You probably have a general impression about how they did "overall". If your grade distribution matches that general sense, then you probably got it about right. I had the luxury of being able to adjust grades upwards (for all) if I felt the individual grades were too low for what I saw as the learning. Never downwards, though. Surprises for students should be happy ones. This ability to adjust depends on some experience, of course.
See this post about imposed curves.