39.13% is the change from 230 to 320
Calculation steps:
[( 320 - 230 ) ÷ 230] x 100 = 39.13%
Formula
Percentage change = [(320 - 230) / 230] x 100
Subtract the new number by the original number
320 - 230 = 90
90 ÷ 230 = 0.391304347826087
0.391304347826087 x 100 = 39.13%