-22.45% is the change from 824 to 639
Calculation steps:
[( 639 - 824 ) ÷ 824] x 100 = -22.45%
Formula
Percentage change = [(639 - 824) / 824] x 100
Subtract the new number by the original number
639 - 824 = -185
-185 ÷ 824 = -0.22451456310679613
-0.22451456310679613 x 100 = -22.45%