28.17% is the change from 71 to 91
Calculation steps:
[( 91 - 71 ) ÷ 71] x 100 = 28.17%
Formula
Percentage change = [(91 - 71) / 71] x 100
Subtract the new number by the original number
91 - 71 = 20
20 ÷ 71 = 0.28169014084507044
0.28169014084507044 x 100 = 28.17%