-1.41% is the change from 639 to 630
Calculation steps:
[( 630 - 639 ) ÷ 639] x 100 = -1.41%
Formula
Percentage change = [(630 - 639) / 639] x 100
Subtract the new number by the original number
630 - 639 = -9
-9 ÷ 639 = -0.014084507042253521
-0.014084507042253521 x 100 = -1.41%