-19.78% is the change from 824 to 661
Calculation steps:
[( 661 - 824 ) ÷ 824] x 100 = -19.78%
Formula
Percentage change = [(661 - 824) / 824] x 100
Subtract the new number by the original number
661 - 824 = -163
-163 ÷ 824 = -0.19781553398058252
-0.19781553398058252 x 100 = -19.78%