-50.48% is the change from 517 to 256
Calculation steps:
[( 256 - 517 ) ÷ 517] x 100 = -50.48%
Formula
Percentage change = [(256 - 517) / 517] x 100
Subtract the new number by the original number
256 - 517 = -261
-261 ÷ 517 = -0.504835589941973
-0.504835589941973 x 100 = -50.48%