13.7% is the change from 270 to 307
Calculation steps:
[( 307 - 270 ) ÷ 270] x 100 = 13.7%
Formula
Percentage change = [(307 - 270) / 270] x 100
Subtract the new number by the original number
307 - 270 = 37
37 ÷ 270 = 0.13703703703703704
0.13703703703703704 x 100 = 13.7%