-21.93% is the change from 643 to 502
Calculation steps:
[( 502 - 643 ) ÷ 643] x 100 = -21.93%
Formula
Percentage change = [(502 - 643) / 643] x 100
Subtract the new number by the original number
502 - 643 = -141
-141 ÷ 643 = -0.2192846034214619
-0.2192846034214619 x 100 = -21.93%