Houston Rockets biggest year-to-year improvement/decline
based on regular season win percentage:

                            Change in 
                              win %
Improvement: 1968 -> 1969     0.268   (0.183 -> 0.451)
Decline:     1982 -> 1983    -0.390   (0.561 -> 0.171)
Last Year:   2007 -> 2008     0.037   (0.634 -> 0.671)