21.96% is the change from 255 to 311
Calculation steps:
[( 311 - 255 ) ÷ 255] x 100 = 21.96%
Formula
Percentage change = [(311 - 255) / 255] x 100
Subtract the new number by the original number
311 - 255 = 56
56 ÷ 255 = 0.2196078431372549
0.2196078431372549 x 100 = 21.96%