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 Milwaukee Bucks           1969 -> 1970     0.354   (0.329 -> 0.683)
  7 Miami Heat                2008 -> 2009     0.341   (0.183 -> 0.524)
  8 Oklahoma City Thunder     2009 -> 2010     0.330   (0.280 -> 0.610)
  8 Phoenix Suns              1988 -> 1989     0.330   (0.341 -> 0.671)
 10 Brooklyn Nets             2001 -> 2002     0.317   (0.317 -> 0.634)
 10 Denver Nuggets            2003 -> 2004     0.317   (0.207 -> 0.524)
 10 Milwaukee Bucks           2014 -> 2015     0.317   (0.183 -> 0.500)
 13 Chicago Bulls             1995 -> 1996     0.305   (0.573 -> 0.878)
 14 Chicago Bulls             2004 -> 2005     0.293   (0.280 -> 0.573)
 14 Cleveland Cavaliers       1991 -> 1992     0.293   (0.402 -> 0.695)
 14 Philadelphia 76ers        2017 -> 2018     0.293   (0.341 -> 0.634)
 17 Phoenix Suns              1969 -> 1970     0.281   (0.195 -> 0.476)
 18 Dallas Mavericks          1994 -> 1995     0.280   (0.159 -> 0.439)
 18 Golden State Warriors     1988 -> 1989     0.280   (0.244 -> 0.524)
 18 Phoenix Suns              2013 -> 2014     0.280   (0.305 -> 0.585)
 21 Atlanta Hawks             2014 -> 2015     0.269   (0.463 -> 0.732)
 21 Memphis Grizzlies         2003 -> 2004     0.269   (0.341 -> 0.610)
 23 Charlotte Hornets         2013 -> 2014     0.268   (0.256 -> 0.524)
 23 Houston Rockets           1968 -> 1969     0.268   (0.183 -> 0.451)
 25 Brooklyn Nets             2012 -> 2013     0.265   (0.333 -> 0.598)
 25 Toronto Raptors           1998 -> 1999     0.265   (0.195 -> 0.460)

    Last season:
    Philadelphia 76ers        2017 -> 2018     0.293   (0.341 -> 0.634)
    Minnesota Timberwolves    2017 -> 2018     0.195   (0.378 -> 0.573)
    New Orleans Pelicans      2017 -> 2018     0.170   (0.415 -> 0.585)
    Houston Rockets           2017 -> 2018     0.122   (0.671 -> 0.793)
    Los Angeles Lakers        2017 -> 2018     0.110   (0.317 -> 0.427)
    Portland Trail Blazers    2017 -> 2018     0.098   (0.500 -> 0.598)
    Toronto Raptors           2017 -> 2018     0.098   (0.622 -> 0.720)
    Brooklyn Nets             2017 -> 2018     0.097   (0.244 -> 0.341)
    Denver Nuggets            2017 -> 2018     0.073   (0.488 -> 0.561)
    Indiana Pacers            2017 -> 2018     0.073   (0.512 -> 0.585)
    Miami Heat                2017 -> 2018     0.037   (0.500 -> 0.537)
    Boston Celtics            2017 -> 2018     0.025   (0.646 -> 0.671)
    Detroit Pistons           2017 -> 2018     0.025   (0.451 -> 0.476)
    Milwaukee Bucks           2017 -> 2018     0.025   (0.512 -> 0.537)
    Oklahoma City Thunder     2017 -> 2018     0.012   (0.573 -> 0.585)