-38.11% is the change from 509 to 315
Calculation steps:
[( 315 - 509 ) ÷ 509] x 100 = -38.11%
Formula
Percentage change = [(315 - 509) / 509] x 100
Subtract the new number by the original number
315 - 509 = -194
-194 ÷ 509 = -0.381139489194499
-0.381139489194499 x 100 = -38.11%