This is the oddest thing I've ever seen posted. You have no idea if it is actual retention without looking who was, for example, an Ice Dog 2 years ago to now. All you are doing in comparing total number of rostered kids. Retention means you continue to hold something. Just say you have 2 Bantam teams totalling 40 players(2 full squads, 4 lines of O, 6 D and 2 goalies on each). Now at Midget, you still have 2 teams, but a total of 38 players. According to your math, that's 95%. Well, what if 10 of those bantams left and you picked up 8 new players. Your retention is really 75%.
I don't get what this even proves. There is so much change at Midget. Kids stop playing club and only play school. There are a few programs who recruit at 16 for Nationals(Ducks, Ice Dogs, Quakers, Warwick) which cause a lot of movement.
I don't see a correlation between retention and winning.