Before they did the re do of club seats and upper decks on East side, it was in the 73,500 seating range from mid 1970s ion, but they'd get crowds of 75,000ish. they had to redo some SW seats when there was some structural issue in '93, so they redid a big ADA section and took out some.
they made some north end zone work before 2006, that pushed it to 80ish, then the other east end work to mid 85s.