My school uses an average as the GPA. I don't know what my "actual" GPA would be but I have a 99,99,99,97,97 making an average of 98.3, this year, my Sophomore year - so far.
Last year I had a 99,99,98,97,96 for the whole year.
For reference, the highest grade my school give is a 99. We cannot get 100s.