-19.32% is the change from 823 to 664
Calculation steps:
[( 664 - 823 ) ÷ 823] x 100 = -19.32%
Formula
Percentage change = [(664 - 823) / 823] x 100
Subtract the new number by the original number
664 - 823 = -159
-159 ÷ 823 = -0.19319562575941676
-0.19319562575941676 x 100 = -19.32%