San Francisco Giants biggest year-to-year improvement/decline
based on regular season win percentage:

                            Change in 
                              win %
Improvement: 1992 -> 1993      19.2   (44.4  ->  63.6)
Decline:     1942 -> 1943     -20.0   (55.9  ->  35.9)
Last Year:   2006 -> 2007      -3.4   (47.2  ->  43.8)