AFC West

Super Bowl winners seldom improve the following season. Chiefs have bucked that trend.

KANSAS CITY, Mo. — With a 13-1 record heading into Sunday’s game against the Atlanta Falcons, the Chiefs have surpassed last year’s victory total. That puts them in a small circle of Super Bowl champions. Of the 54 winners, the Chiefs are only the ninth team to improve their record over the previous season. The Chiefs were 12-4 last season. Six Super Bowl winners finished with the same record as their championship year, and 39 had a worse record. The biggest drop in record for a Super Bowl champ: the 1999 Denver Broncos, who cratered after winning the Super Bowl, falling from 14-2 in John Elwa…