I have this poster and its pretty neat. But there could have been more rings. NU had 40 bowl games, 22 conference championships and 5 NCs during this era. But some of the early years did not have rings made.
Western Interstate University Football Association - won or shared -3
Missouri Valley Conference - won or shared - 12
Big 6 - Won or shared - 9
Big 8 - Won or shared - 20
Big 12 - 2
1970 - AP
Other years mentioned by at least one selector -1915- 1921-1980-81-82-83-84-1993-99