-17.13% is the change from 800 to 663
Calculation steps:
[( 663 - 800 ) ÷ 800] x 100 = -17.13%
Formula
Percentage change = [(663 - 800) / 800] x 100
Subtract the new number by the original number
663 - 800 = -137
-137 ÷ 800 = -0.17125
-0.17125 x 100 = -17.13%