-7.13% is the change from 687 to 638
Calculation steps:
[( 638 - 687 ) ÷ 687] x 100 = -7.13%
Formula
Percentage change = [(638 - 687) / 687] x 100
Subtract the new number by the original number
638 - 687 = -49
-49 ÷ 687 = -0.07132459970887918
-0.07132459970887918 x 100 = -7.13%