-3.16% is the change from 664 to 643
Calculation steps:
[( 643 - 664 ) ÷ 664] x 100 = -3.16%
Formula
Percentage change = [(643 - 664) / 664] x 100
Subtract the new number by the original number
643 - 664 = -21
-21 ÷ 664 = -0.03162650602409638
-0.03162650602409638 x 100 = -3.16%