-23.04% is the change from 638 to 491
Calculation steps:
[( 491 - 638 ) ÷ 638] x 100 = -23.04%
Formula
Percentage change = [(491 - 638) / 638] x 100
Subtract the new number by the original number
491 - 638 = -147
-147 ÷ 638 = -0.2304075235109718
-0.2304075235109718 x 100 = -23.04%