I chose to highlight this particular stat because it's the one Pelini harped on a couple years ago in an interview. If you exclude the Callahan era altogether, you'll notice a roughly 3 point increment from Devaney to Osborne to Solich to Pelini.
These are just pure numbers. No agenda on my part. I'm not interested in debating the differences between each era. However, I'd be remiss not to acknowledge how much the game has evolved since 1962. Interpret away as you wish.
DEVANEY ERA
1962 - 12.7
1963 - 10.7
1964 - 7.5
1965 - 9.0
1966 - 8.4
1967 - 8.3
1968 - 16.1
1969 - 10.8
1970 - 15.8
1971 - 8.0
1972 - 8.1
Average = 10.4
OSBORNE ERA
1973 - 13.6
1974 - 11.0
1975 - 13.0
1976 - 13.9
1977 - 16.7
1978 - 18.0
1979 - 10.9
1980 - 8.5
1981 - 9.4
1982 - 12.3
1983 - 15.5
1984 - 9.5 -
1985 - 12.4
1986 - 13.6
1987 - 12.1
1988 - 15.2
1989 - 15.8
1990 - 13.4
1991 - 18.9
1992 - 15.6
1993 - 16.0
1994 - 12.1
1995 - 13.6
1996 - 12.8
1997 - 16.4
Average = 13.6
SOLICH ERA
1998 - 15.2
1999 - 12.5
2000 - 19.4
2001 - 15.8
2002 - 23.9
2003 - 14.5
Average = 16.8
CALLAHAN ERA
2004 - 27.1
2005 - 21.0
2006 - 18.3
2007 - 37.9
Average = 26.1
PELINI ERA
2008 - 28.5
2009 - 10.4
2010 - 17.4
2011 - 23.4
Average = 19.9