-51.79% is the change from 168 to 81
Calculation steps:
[( 81 - 168 ) ÷ 168] x 100 = -51.79%
Formula
Percentage change = [(81 - 168) / 168] x 100
Subtract the new number by the original number
81 - 168 = -87
-87 ÷ 168 = -0.5178571428571429
-0.5178571428571429 x 100 = -51.79%