-38.83% is the change from 515 to 315
Calculation steps:
[( 315 - 515 ) ÷ 515] x 100 = -38.83%
Formula
Percentage change = [(315 - 515) / 515] x 100
Subtract the new number by the original number
315 - 515 = -200
-200 ÷ 515 = -0.3883495145631068
-0.3883495145631068 x 100 = -38.83%