Tampa Bay Rays : biggest year-to-year improvement/decline

Based on regular season win percentage:

                            Change in 
                              win %
Improvement: 2007 -> 2008      19.2   (40.7  ->  59.9)
Decline:     2013 -> 2014      -8.9   (56.4  ->  47.5)
Last Year:   2017 -> 2018       6.2   (49.4  ->  55.6)