-0.2% is the change from 500 to 499
Calculation steps:
[( 499 - 500 ) ÷ 500] x 100 = -0.2%
Formula
Percentage change = [(499 - 500) / 500] x 100
Subtract the new number by the original number
499 - 500 = -1
-1 ÷ 500 = -0.002
-0.002 x 100 = -0.2%
Example