-20.43% is the change from 509 to 405
Calculation steps:
[( 405 - 509 ) ÷ 509] x 100 = -20.43%
Formula
Percentage change = [(405 - 509) / 509] x 100
Subtract the new number by the original number
405 - 509 = -104
-104 ÷ 509 = -0.2043222003929273
-0.2043222003929273 x 100 = -20.43%