-40.44% is the change from 136 to 81
Calculation steps:
[( 81 - 136 ) ÷ 136] x 100 = -40.44%
Formula
Percentage change = [(81 - 136) / 136] x 100
Subtract the new number by the original number
81 - 136 = -55
-55 ÷ 136 = -0.40441176470588236
-0.40441176470588236 x 100 = -40.44%