13.57% is the change from 280 to 318
Calculation steps:
[( 318 - 280 ) ÷ 280] x 100 = 13.57%
Formula
Percentage change = [(318 - 280) / 280] x 100
Subtract the new number by the original number
318 - 280 = 38
38 ÷ 280 = 0.1357142857142857
0.1357142857142857 x 100 = 13.57%