Since "youth" seems to be a word use...and the proverbial "future is bright" ....
I don't have time or energy....
Maybe a numbers guy or one of the retired guys on here can do it... ;-) I'll do OU.
OU # SR - 22 (RS or not, starter or not)
# JR - 17
# SO - 33
#FR - 37
out of the 70/109 total are So/Fr redshirt, I counted about 16 that I've seen/heard play in games. Some starters, some here and there. 64% of total team roster is considered underclassman 70/109. With 16/24 - 66% (starting positions, counted punter and kicker but not deep snapper, or playing time) being underclassman as well.
Okay...so someone do ksu/bu/tcu~