I just researched a bunch of pass/run ratios, mostly for the national champions going back to 1971 for my game.
Some findings to share:
the only 50/50 NC was 1993 FSU
no one else was even 49/51 nor 51/49, so they were unique
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1975 OU was the run-heaviest at 91%
1984 BYU was the pass-happiest at 55%
Aside from BYU, no one exceeded 52%, though several peaked at it: 1989 Miami, 1991 Miami, 1999 FSU, 2000 OU, 2016 Clemson
This 52/48 ratio was the most popular individual ratio of the NCs researched.
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Some surprises (to me):
2004 USC, 2013 FSU and 2018 Clemson "only" threw it 47% of the time
1994 PSU only passed it 40%, which seems low to me
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1997 Nebraska ran it far more than anyone else recently, at 81%, and all the way back to 1985 OU, which ran it 87%
And since 1997, the highest run percentage for a NC is shared by 2002 OSU and 2010 Auburn (69%)
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Some couplings (same ratios):
1983 Miami & 2006 Florida (46 pass/54 run)
1981 Clemson & 1994 Nebraska (23/77)
1980 Georgia & 1988 ND (22/78)
1982 Penn St & 1991 Washington (39/61)
1972 USC & 1986 Penn St (30/70)
1977 ND & 1992 Alabama (32/68)
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And for those who love round numbers:
20/80 - 1978 Alabama & 1974 USC
30/70 - 1972 USC & 1986 PSU
40/60 - 2003 LSU
50/50 - 1993 FSU
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A popular ratio: 37 pass/63 run
shared by 1997 Michigan, 2009 Alabama, 2012 Alabama, and 2014 Ohio St