-68.63% is the change from 255 to 80
Calculation steps:
[( 80 - 255 ) ÷ 255] x 100 = -68.63%
Formula
Percentage change = [(80 - 255) / 255] x 100
Subtract the new number by the original number
80 - 255 = -175
-175 ÷ 255 = -0.6862745098039216
-0.6862745098039216 x 100 = -68.63%