Yahoo has it as
6) ACC
5) MWC
4) PAC 12
3) SEC
2) B1G
1) Big 12
Guess they based this on OOC P5 games.
Big 12 played the most OOC P5 games and had the highest winning percentage.
Atlantic Coast (6).
Non-conference record: 20-10, .667 winning percentage.
Record vs. Power Five opponents; 3-7, .300.
Road/neutral record: 6-5, .546.
Percentage of non-conference games played away from home: 36.7.
Best wins: Clemson over Texas A&M; Wake Forest over North Carolina*; North Carolina over South Carolina.
Worst losses: Georgia Tech to Citadel; Florida State to Boise State; Boston College to Kansas; North Carolina State at West Virginia.
Percentage of non-conference games against FCS opponents: 23.3.
Big 12 (1).
Non-conference record: 22-5, .815 winning percentage.
Record vs. Power Five opponents: 6-4, .600.
Road/neutral record: 7-2, .778
Percentage of non-conference games played away from home: 33.
Best wins: Kansas State at Mississippi State; Kansas at Boston College; TCU at Purdue; West Virginia over North Carolina State.
Worst losses: Kansas to Coastal Carolina; Texas Tech at Arizona.
Percentage of non-conference games against FCS opponents: 29.7 (8-0 record).