-49.41% is the change from 506 to 256
Calculation steps:
[( 256 - 506 ) ÷ 506] x 100 = -49.41%
Formula
Percentage change = [(256 - 506) / 506] x 100
Subtract the new number by the original number
256 - 506 = -250
-250 ÷ 506 = -0.49407114624505927
-0.49407114624505927 x 100 = -49.41%