-52.63% is the change from 171 to 81
Calculation steps:
[( 81 - 171 ) ÷ 171] x 100 = -52.63%
Formula
Percentage change = [(81 - 171) / 171] x 100
Subtract the new number by the original number
81 - 171 = -90
-90 ÷ 171 = -0.5263157894736842
-0.5263157894736842 x 100 = -52.63%