-22.53% is the change from 821 to 636
Calculation steps:
[( 636 - 821 ) ÷ 821] x 100 = -22.53%
Formula
Percentage change = [(636 - 821) / 821] x 100
Subtract the new number by the original number
636 - 821 = -185
-185 ÷ 821 = -0.22533495736906212
-0.22533495736906212 x 100 = -22.53%