Interesting tool here -- you can see across history what percentage of a team's (or many teams') stadiums they filled, on average. In other words, over the last 50 years, what percentage of Colt Stadium/the Dome/MMP did the Astros fill, on average?
https://public.tableau.com/profile/scott.lindholm#!/vizhome/MLB1871-2015/CapacityKind of fun to play around in. I was surprised, for instance, to see Wrigley not all that full, historically, until just the last few years.