11.15% is the change from 278 to 309
Calculation steps:
[( 309 - 278 ) ÷ 278] x 100 = 11.15%
Formula
Percentage change = [(309 - 278) / 278] x 100
Subtract the new number by the original number
309 - 278 = 31
31 ÷ 278 = 0.11151079136690648
0.11151079136690648 x 100 = 11.15%