New York Jets : biggest year-to-year improvement/decline

Based on regular season win percentage:

                            Change in 
                              win %
Improvement: 1996 -> 1997     0.501   (0.062 -> 0.563)
Decline:     1969 -> 1970    -0.428   (0.714 -> 0.286)
Last Year:   2019 -> 2020    -0.313   (0.438 -> 0.125)