-0.2% is the change from 502 to 501
Calculation steps:
[( 501 - 502 ) ÷ 502] x 100 = -0.2%
Formula
Percentage change = [(501 - 502) / 502] x 100
Subtract the new number by the original number
501 - 502 = -1
-1 ÷ 502 = -0.00199203187250996
-0.00199203187250996 x 100 = -0.2%