-21.91% is the change from 639 to 499
Calculation steps:
[( 499 - 639 ) ÷ 639] x 100 = -21.91%
Formula
Percentage change = [(499 - 639) / 639] x 100
Subtract the new number by the original number
499 - 639 = -140
-140 ÷ 639 = -0.2190923317683881
-0.2190923317683881 x 100 = -21.91%