-79.41% is the change from 102 to 21
Calculation steps:
[( 21 - 102 ) ÷ 102] x 100 = -79.41%
Formula
Percentage change = [(21 - 102) / 102] x 100
Subtract the new number by the original number
21 - 102 = -81
-81 ÷ 102 = -0.7941176470588235
-0.7941176470588235 x 100 = -79.41%