-20.04% is the change from 499 to 399
Calculation steps:
[( 399 - 499 ) ÷ 499] x 100 = -20.04%
Formula
Percentage change = [(399 - 499) / 499] x 100
Subtract the new number by the original number
399 - 499 = -100
-100 ÷ 499 = -0.20040080160320642
-0.20040080160320642 x 100 = -20.04%