-16.42% is the change from 609 to 509
Calculation steps:
[( 509 - 609 ) ÷ 609] x 100 = -16.42%
Formula
Percentage change = [(509 - 609) / 609] x 100
Subtract the new number by the original number
509 - 609 = -100
-100 ÷ 609 = -0.16420361247947454
-0.16420361247947454 x 100 = -16.42%