-21.79% is the change from 638 to 499
Calculation steps:
[( 499 - 638 ) ÷ 638] x 100 = -21.79%
Formula
Percentage change = [(499 - 638) / 638] x 100
Subtract the new number by the original number
499 - 638 = -139
-139 ÷ 638 = -0.21786833855799373
-0.21786833855799373 x 100 = -21.79%