-34.53% is the change from 391 to 256
Calculation steps:
[( 256 - 391 ) ÷ 391] x 100 = -34.53%
Formula
Percentage change = [(256 - 391) / 391] x 100
Subtract the new number by the original number
256 - 391 = -135
-135 ÷ 391 = -0.3452685421994885
-0.3452685421994885 x 100 = -34.53%