-50.29% is the change from 515 to 256
Calculation steps:
[( 256 - 515 ) ÷ 515] x 100 = -50.29%
Formula
Percentage change = [(256 - 515) / 515] x 100
Subtract the new number by the original number
256 - 515 = -259
-259 ÷ 515 = -0.5029126213592233
-0.5029126213592233 x 100 = -50.29%