-39.69% is the change from 509 to 307
Calculation steps:
[( 307 - 509 ) ÷ 509] x 100 = -39.69%
Formula
Percentage change = [(307 - 509) / 509] x 100
Subtract the new number by the original number
307 - 509 = -202
-202 ÷ 509 = -0.3968565815324165
-0.3968565815324165 x 100 = -39.69%