It all depends upon where you go.
Please don't take this as one-ups-manship, but I have seen far more than that on a single dive. I would guess, in fact, that I saw at least 1,500 hammerheads in a 3-4 day stretch one time.
There are places that are full of sharks, and there are places where a single sighting is a wonder worthy of exalted talk after the dive.
No one-ups needed. We're so new that pretty much anybody cna one up us.
We've seen all our sharks in dives off Cancun. Apparently not all that common in that area, but not unheard of either. We've had two single-shark encounters, and one pair; a gray reef shark (4 footer) who circled us about 30 feet out, and a nurse shark (5 footer) who came in to visit and kissed the camera. I stuck up a clip in another thread.