-36.09% is the change from 399 to 255
Calculation steps:
[( 255 - 399 ) ÷ 399] x 100 = -36.09%
Formula
Percentage change = [(255 - 399) / 399] x 100
Subtract the new number by the original number
255 - 399 = -144
-144 ÷ 399 = -0.3609022556390977
-0.3609022556390977 x 100 = -36.09%