* School grading systems: Some schools use a 4.0 scale, others a 5.0 scale, and some might use letter grades without a numerical equivalent.
* School demographics: Student performance can vary significantly between schools in different communities.
* Course difficulty: A student taking more challenging courses might have a lower GPA than a student taking easier courses, even if their performance is equally strong.
Therefore, any number you might find cited as an "average" would be highly generalized and not particularly meaningful.