-0.78% is the change from 255 to 253
Calculation steps:
[( 253 - 255 ) ÷ 255] x 100 = -0.78%
Formula
Percentage change = [(253 - 255) / 255] x 100
Subtract the new number by the original number
253 - 255 = -2
-2 ÷ 255 = -0.00784313725490196
-0.00784313725490196 x 100 = -0.78%