-49.71% is the change from 509 to 256
Calculation steps:
[( 256 - 509 ) ÷ 509] x 100 = -49.71%
Formula
Percentage change = [(256 - 509) / 509] x 100
Subtract the new number by the original number
256 - 509 = -253
-253 ÷ 509 = -0.49705304518664045
-0.49705304518664045 x 100 = -49.71%