-29.63% is the change from 81 to 57
Calculation steps:
[( 57 - 81 ) ÷ 81] x 100 = -29.63%
Formula
Percentage change = [(57 - 81) / 81] x 100
Subtract the new number by the original number
57 - 81 = -24
-24 ÷ 81 = -0.2962962962962963
-0.2962962962962963 x 100 = -29.63%