12.5% is the change from 72 to 81
Calculation steps:
[( 81 - 72 ) ÷ 72] x 100 = 12.5%
Formula
Percentage change = [(81 - 72) / 72] x 100
Subtract the new number by the original number
81 - 72 = 9
9 ÷ 72 = 0.125
0.125 x 100 = 12.5%
Example