-75.29% is the change from 255 to 63
Calculation steps:
[( 63 - 255 ) ÷ 255] x 100 = -75.29%
Formula
Percentage change = [(63 - 255) / 255] x 100
Subtract the new number by the original number
63 - 255 = -192
-192 ÷ 255 = -0.7529411764705882
-0.7529411764705882 x 100 = -75.29%