San Diego Padres biggest year-to-year improvement/decline
based on regular season win percentage:

                            Change in 
                              win %
Improvement: 2003 -> 2004      14.2   (39.5  ->  53.7)
Decline:     1998 -> 1999     -14.8   (60.5  ->  45.7)
Last Year:   2006 -> 2007       0.3   (54.3  ->  54.6)