-23.39% is the change from 171 to 131
Calculation steps:
[( 131 - 171 ) ÷ 171] x 100 = -23.39%
Formula
Percentage change = [(131 - 171) / 171] x 100
Subtract the new number by the original number
131 - 171 = -40
-40 ÷ 171 = -0.23391812865497075
-0.23391812865497075 x 100 = -23.39%