Oklahoma City Thunder biggest year-to-year improvement/decline

Based on regular season win percentage:

                            Change in 
                              win %
Improvement: 2009 -> 2010     0.330   (0.280 -> 0.610)
Decline:     2020 -> 2021    -0.305   (0.611 -> 0.306)
Last Year:   2025 -> 2026    -0.049   (0.829 -> 0.780)