-17.88% is the change from 509 to 418
Calculation steps:
[( 418 - 509 ) ÷ 509] x 100 = -17.88%
Formula
Percentage change = [(418 - 509) / 509] x 100
Subtract the new number by the original number
418 - 509 = -91
-91 ÷ 509 = -0.1787819253438114
-0.1787819253438114 x 100 = -17.88%