-20.1% is the change from 821 to 656
Calculation steps:
[( 656 - 821 ) ÷ 821] x 100 = -20.1%
Formula
Percentage change = [(656 - 821) / 821] x 100
Subtract the new number by the original number
656 - 821 = -165
-165 ÷ 821 = -0.20097442143727162
-0.20097442143727162 x 100 = -20.1%