-1.1% is the change from 638 to 631
Calculation steps:
[( 631 - 638 ) ÷ 638] x 100 = -1.1%
Formula
Percentage change = [(631 - 638) / 638] x 100
Subtract the new number by the original number
631 - 638 = -7
-7 ÷ 638 = -0.0109717868338558
-0.0109717868338558 x 100 = -1.1%