-21.04% is the change from 808 to 638
Calculation steps:
[( 638 - 808 ) ÷ 808] x 100 = -21.04%
Formula
Percentage change = [(638 - 808) / 808] x 100
Subtract the new number by the original number
638 - 808 = -170
-170 ÷ 808 = -0.2103960396039604
-0.2103960396039604 x 100 = -21.04%