-0.62% is the change from 643 to 639
Calculation steps:
[( 639 - 643 ) ÷ 643] x 100 = -0.62%
Formula
Percentage change = [(639 - 643) / 643] x 100
Subtract the new number by the original number
639 - 643 = -4
-4 ÷ 643 = -0.006220839813374806
-0.006220839813374806 x 100 = -0.62%