-22.78% is the change from 821 to 634
Calculation steps:
[( 634 - 821 ) ÷ 821] x 100 = -22.78%
Formula
Percentage change = [(634 - 821) / 821] x 100
Subtract the new number by the original number
634 - 821 = -187
-187 ÷ 821 = -0.22777101096224117
-0.22777101096224117 x 100 = -22.78%