-4.35% is the change from 643 to 615
Calculation steps:
[( 615 - 643 ) ÷ 643] x 100 = -4.35%
Formula
Percentage change = [(615 - 643) / 643] x 100
Subtract the new number by the original number
615 - 643 = -28
-28 ÷ 643 = -0.04354587869362364
-0.04354587869362364 x 100 = -4.35%