-0.93% is the change from 643 to 637
Calculation steps:
[( 637 - 643 ) ÷ 643] x 100 = -0.93%
Formula
Percentage change = [(637 - 643) / 643] x 100
Subtract the new number by the original number
637 - 643 = -6
-6 ÷ 643 = -0.00933125972006221
-0.00933125972006221 x 100 = -0.93%