A much better way to look at this is to look at the percentage of each ground which is empty on average.
Newcastle (2730 seats, capacity= 52387) 5.2%
Sunderland (8829 seats, capacity= 49000) 18.02%
QPR (1297 seats, capacity= 20000) 6.49%
Wigan (6479 seats, capacity= 25138) 25.77%...