-21.87% is the change from 823 to 643
Calculation steps:
[( 643 - 823 ) ÷ 823] x 100 = -21.87%
Formula
Percentage change = [(643 - 823) / 823] x 100
Subtract the new number by the original number
643 - 823 = -180
-180 ÷ 823 = -0.2187120291616039
-0.2187120291616039 x 100 = -21.87%