Yeah 15 is pretty normal now-a-days. I played a game about a week ago with Gravity Kitty... don't remember how many tanks, but we defibbed probably 20 times, the round took almost an hour and was sooo fun just to see if we'd make it and we did. Actually, infected kept buying witches. There had to have been 50 witches in the entire map. I think I killed almost 700 common.