-21.16% is the change from 638 to 503
Calculation steps:
[( 503 - 638 ) ÷ 638] x 100 = -21.16%
Formula
Percentage change = [(503 - 638) / 638] x 100
Subtract the new number by the original number
503 - 638 = -135
-135 ÷ 638 = -0.2115987460815047
-0.2115987460815047 x 100 = -21.16%