-22.09% is the change from 815 to 635
Calculation steps:
[( 635 - 815 ) ÷ 815] x 100 = -22.09%
Formula
Percentage change = [(635 - 815) / 815] x 100
Subtract the new number by the original number
635 - 815 = -180
-180 ÷ 815 = -0.22085889570552147
-0.22085889570552147 x 100 = -22.09%