-52.35% is the change from 170 to 81
Calculation steps:
[( 81 - 170 ) ÷ 170] x 100 = -52.35%
Formula
Percentage change = [(81 - 170) / 170] x 100
Subtract the new number by the original number
81 - 170 = -89
-89 ÷ 170 = -0.5235294117647059
-0.5235294117647059 x 100 = -52.35%