-20.9% is the change from 823 to 651
Calculation steps:
[( 651 - 823 ) ÷ 823] x 100 = -20.9%
Formula
Percentage change = [(651 - 823) / 823] x 100
Subtract the new number by the original number
651 - 823 = -172
-172 ÷ 823 = -0.20899149453219928
-0.20899149453219928 x 100 = -20.9%