Mountaineer Field season attendance, according to Wikipedia:
2011 56,532 last season in Big East
2012 49,344 Big 12 seasons begin
2013 53,076
2014 56,686
2015 54,826
2016 57,383
Overall, 403,000 fans home and away, 5th best in 37 years of new Mountaineer Field in 2016.
So, 3 of 5 Big 12 seasons had lower average attendance than final 2011 season in the Big East.
This is convoluted math because Wikipedia listed attendance by the games and I had to add the totals and divide by the number of games in MF that season so I may have made errors. If anyone has clearer, more official numbers I’d love to see them.