The best years *ever* (79-83) for the Expos averaged 26-28k a game. That's when the Big O was fairly new and was an attraction by itself. And these were the Gary Carter, Andre Dawson, Tim Raines, etc. years.
Even in the strike-shortened season of 1994 when they had an awesome team that led the majors, they only averaged 22-23k.
http://exposnation.com/assistance-pa...s-de-montreal/