Percent change = change in value/original value.
13) 75 -> 38: 37 decrease/75 original
49.3333333333333% decrease
about 49% decreaase
14) 97 -> 3: 94 decreace/97 original
96.9072164948454% decrease
about 97% decrease
15) 77 -> 55: 22 decrease/77 original
28.5714285714286% decrease
about 29% decrease
16) 67 -> 28: 39 decrease/67 original
58.2089552238806% decrease
about 58% decrease