Depends on the program, the game and often the weather. STVM is a second year program and averaging mid 70s. A school like Hudson is going to bring in around 400-500.
In 2013 Mason played Moeller for the southwest regional championship at Mason's lacrosse/soccer stadium. There was standing room only on both sides of the field. It was reported that over 2000 tickets were sold at the gate. I am guessing there was at least 2500 to 3000 people at the game. It was an incredible game, one of the most exciting sporting events I have ever attended.