-20.71% is the change from 821 to 651
Calculation steps:
[( 651 - 821 ) ÷ 821] x 100 = -20.71%
Formula
Percentage change = [(651 - 821) / 821] x 100
Subtract the new number by the original number
651 - 821 = -170
-170 ÷ 821 = -0.20706455542021923
-0.20706455542021923 x 100 = -20.71%