-74.39% is the change from 82 to 21
Calculation steps:
[( 21 - 82 ) ÷ 82] x 100 = -74.39%
Formula
Percentage change = [(21 - 82) / 82] x 100
Subtract the new number by the original number
21 - 82 = -61
-61 ÷ 82 = -0.7439024390243902
-0.7439024390243902 x 100 = -74.39%