-20.63% is the change from 800 to 635
Calculation steps:
[( 635 - 800 ) ÷ 800] x 100 = -20.63%
Formula
Percentage change = [(635 - 800) / 800] x 100
Subtract the new number by the original number
635 - 800 = -165
-165 ÷ 800 = -0.20625
-0.20625 x 100 = -20.63%