What NFL running back has the highest average yards per carry for a whole carrier?

I think Walter Payton did have the record over Jim Brown, but i think Emmit Smith Broke the record. Walter Payton had all 13 Seasons with 1000 rushing yards or more, and had the record for most yards in a game, but i think it was broken just recently. But i do still think Walter Payton is the Best Running Back of all time. ---- As of the 2008 season, that record is held by Jim Brown with 104.3 rushing yards per game. Barry Sanders is second at 99.8 rushing yards per game and Terrell Davis is third at 97.5. Payton is 8th with 88.0 rushing yards per game and Emmitt Smith is 17th at 81.2.