-21.13% is the change from 800 to 631
Calculation steps:
[( 631 - 800 ) ÷ 800] x 100 = -21.13%
Formula
Percentage change = [(631 - 800) / 800] x 100
Subtract the new number by the original number
631 - 800 = -169
-169 ÷ 800 = -0.21125
-0.21125 x 100 = -21.13%