I did compare 2013-2015 (8-5) versus 2016-2018 (4-7). I would expect Bronco's numbers over time are better than the 8-5 as 2014 seemed to be such a freakishly odd season.
If we go all the way back to the Lavell era, we'd probably want to start looking at G5 schools with winning records as bowl games were much less common.