-3.02% is the change from 663 to 643
Calculation steps:
[( 643 - 663 ) ÷ 663] x 100 = -3.02%
Formula
Percentage change = [(643 - 663) / 663] x 100
Subtract the new number by the original number
643 - 663 = -20
-20 ÷ 663 = -0.030165912518853696
-0.030165912518853696 x 100 = -3.02%