-39.1% is the change from 509 to 310
Calculation steps:
[( 310 - 509 ) ÷ 509] x 100 = -39.1%
Formula
Percentage change = [(310 - 509) / 509] x 100
Subtract the new number by the original number
310 - 509 = -199
-199 ÷ 509 = -0.39096267190569745
-0.39096267190569745 x 100 = -39.1%