51.17% is the change from 256 to 387
Calculation steps:
[( 387 - 256 ) ÷ 256] x 100 = 51.17%
Formula
Percentage change = [(387 - 256) / 256] x 100
Subtract the new number by the original number
387 - 256 = 131
131 ÷ 256 = 0.51171875
0.51171875 x 100 = 51.17%