-3.14% is the change from 255 to 247
Calculation steps:
[( 247 - 255 ) ÷ 255] x 100 = -3.14%
Formula
Percentage change = [(247 - 255) / 255] x 100
Subtract the new number by the original number
247 - 255 = -8
-8 ÷ 255 = -0.03137254901960784
-0.03137254901960784 x 100 = -3.14%