-99.61% is the change from 255 to 1
Calculation steps:
[( 1 - 255 ) ÷ 255] x 100 = -99.61%
Formula
Percentage change = [(1 - 255) / 255] x 100
Subtract the new number by the original number
1 - 255 = -254
-254 ÷ 255 = -0.996078431372549
-0.996078431372549 x 100 = -99.61%