Kansas City Chiefs : biggest year-to-year improvement/decline

Based on regular season win percentage:

                            Change in 
                              win %
Improvement: 2012 -> 2013     0.563   (0.125 -> 0.688)
Decline:     2003 -> 2004    -0.375   (0.813 -> 0.438)
Last Year:   2022 -> 2023    -0.177   (0.824 -> 0.647)