New England Patriots : biggest year-to-year improvement/decline

Based on regular season win percentage:

                            Change in 
                              win %
Improvement: 2024 -> 2025     0.589   (0.235 -> 0.824)
Decline:     1980 -> 1981    -0.500   (0.625 -> 0.125)
Last Year:   2024 -> 2025     0.589   (0.235 -> 0.824)