31.49% is the change from 235 to 309
Calculation steps:
[( 309 - 235 ) ÷ 235] x 100 = 31.49%
Formula
Percentage change = [(309 - 235) / 235] x 100
Subtract the new number by the original number
309 - 235 = 74
74 ÷ 235 = 0.3148936170212766
0.3148936170212766 x 100 = 31.49%