-21.98% is the change from 828 to 646
Calculation steps:
[( 646 - 828 ) ÷ 828] x 100 = -21.98%
Formula
Percentage change = [(646 - 828) / 828] x 100
Subtract the new number by the original number
646 - 828 = -182
-182 ÷ 828 = -0.21980676328502416
-0.21980676328502416 x 100 = -21.98%