-74.07% is the change from 81 to 21
Calculation steps:
[( 21 - 81 ) ÷ 81] x 100 = -74.07%
Formula
Percentage change = [(21 - 81) / 81] x 100
Subtract the new number by the original number
21 - 81 = -60
-60 ÷ 81 = -0.7407407407407407
-0.7407407407407407 x 100 = -74.07%