-20.47% is the change from 171 to 136
Calculation steps:
[( 136 - 171 ) ÷ 171] x 100 = -20.47%
Formula
Percentage change = [(136 - 171) / 171] x 100
Subtract the new number by the original number
136 - 171 = -35
-35 ÷ 171 = -0.2046783625730994
-0.2046783625730994 x 100 = -20.47%