-18.93% is the change from 824 to 668
Calculation steps:
[( 668 - 824 ) ÷ 824] x 100 = -18.93%
Formula
Percentage change = [(668 - 824) / 824] x 100
Subtract the new number by the original number
668 - 824 = -156
-156 ÷ 824 = -0.18932038834951456
-0.18932038834951456 x 100 = -18.93%