Interesting numbers. Thanks. It seems that viewership numbers generally reflect the channel more than the team that is playing. A game on CBS or ESPN will draw more viewers than a game on ESPNU, even if the teams playing on ESPNU have a wider following. And a game that kicks off at 7PM Eastern will have higher numbers than a game that starts at 11 PM Eastern. So the average viewership number seems to be a bit misleading because it does not account for the significant time-slot/channel factors.
If you have them, it would be interesting to see how BYU's numbers compare against others on the same channel during the same time-slot. This may be easier to do for the Thursday/Friday games because there is generally only 1 or 2 Thursday/Friday games per week on the ESPN networks.