NBA : Biggest year to year improvements from one season to the
next (based on regular season win percentage):
                                             Change in
       Franchise                               win %
  1 Boston Celtics            2007 -> 2008     0.512   (0.293 -> 0.805)
  2 San Antonio Spurs         1997 -> 1998     0.439   (0.244 -> 0.683)
  3 San Antonio Spurs         1989 -> 1990     0.427   (0.256 -> 0.683)
  4 Phoenix Suns              2004 -> 2005     0.402   (0.354 -> 0.756)
  5 Boston Celtics            1979 -> 1980     0.390   (0.354 -> 0.744)
  6 Detroit Pistons           2024 -> 2025     0.366   (0.171 -> 0.537)
  7 Milwaukee Bucks           1969 -> 1970     0.354   (0.329 -> 0.683)
  8 Miami Heat                2008 -> 2009     0.341   (0.183 -> 0.524)
  9 Oklahoma City Thunder     2009 -> 2010     0.330   (0.280 -> 0.610)
  9 Phoenix Suns              1988 -> 1989     0.330   (0.341 -> 0.671)
 11 Brooklyn Nets             2001 -> 2002     0.317   (0.317 -> 0.634)
 11 Denver Nuggets            2003 -> 2004     0.317   (0.207 -> 0.524)
 11 Milwaukee Bucks           2014 -> 2015     0.317   (0.183 -> 0.500)
 14 Golden State Warriors     2020 -> 2021     0.311   (0.231 -> 0.542)
 15 Chicago Bulls             1995 -> 1996     0.305   (0.573 -> 0.878)
 16 Chicago Bulls             2004 -> 2005     0.293   (0.280 -> 0.573)
 16 Cleveland Cavaliers       1991 -> 1992     0.293   (0.402 -> 0.695)
 16 Philadelphia 76ers        2017 -> 2018     0.293   (0.341 -> 0.634)
 19 Los Angeles Lakers        2019 -> 2020     0.281   (0.451 -> 0.732)
 19 Phoenix Suns              1969 -> 1970     0.281   (0.195 -> 0.476)
 21 Dallas Mavericks          1994 -> 1995     0.280   (0.159 -> 0.439)
 21 Golden State Warriors     1988 -> 1989     0.280   (0.244 -> 0.524)
 21 Phoenix Suns              2013 -> 2014     0.280   (0.305 -> 0.585)
 24 Atlanta Hawks             2020 -> 2021     0.270   (0.299 -> 0.569)
 25 Atlanta Hawks             2014 -> 2015     0.269   (0.463 -> 0.732)
 25 Memphis Grizzlies         2003 -> 2004     0.269   (0.341 -> 0.610)

    Last season:
    Detroit Pistons           2024 -> 2025     0.366   (0.171 -> 0.537)
    Memphis Grizzlies         2024 -> 2025     0.256   (0.329 -> 0.585)
    Cleveland Cavaliers       2024 -> 2025     0.195   (0.585 -> 0.780)
    Portland Trail Blazers    2024 -> 2025     0.183   (0.256 -> 0.439)
    San Antonio Spurs         2024 -> 2025     0.147   (0.268 -> 0.415)
    Houston Rockets           2024 -> 2025     0.134   (0.500 -> 0.634)
    Oklahoma City Thunder     2024 -> 2025     0.134   (0.695 -> 0.829)
    Toronto Raptors           2024 -> 2025     0.061   (0.305 -> 0.366)
    Atlanta Hawks             2024 -> 2025     0.049   (0.439 -> 0.488)
    Indiana Pacers            2024 -> 2025     0.037   (0.573 -> 0.610)
    Los Angeles Lakers        2024 -> 2025     0.037   (0.573 -> 0.610)
    Washington Wizards        2024 -> 2025     0.037   (0.183 -> 0.220)
    Golden State Warriors     2024 -> 2025     0.024   (0.561 -> 0.585)
    New York Knickerbockers   2024 -> 2025     0.012   (0.610 -> 0.622)