-18.65% is the change from 815 to 663
Calculation steps:
[( 663 - 815 ) ÷ 815] x 100 = -18.65%
Formula
Percentage change = [(663 - 815) / 815] x 100
Subtract the new number by the original number
663 - 815 = -152
-152 ÷ 815 = -0.18650306748466258
-0.18650306748466258 x 100 = -18.65%