-20.04% is the change from 509 to 407
Calculation steps:
[( 407 - 509 ) ÷ 509] x 100 = -20.04%
Formula
Percentage change = [(407 - 509) / 509] x 100
Subtract the new number by the original number
407 - 509 = -102
-102 ÷ 509 = -0.20039292730844793
-0.20039292730844793 x 100 = -20.04%