38.53% is the change from 231 to 320
Calculation steps:
[( 320 - 231 ) ÷ 231] x 100 = 38.53%
Formula
Percentage change = [(320 - 231) / 231] x 100
Subtract the new number by the original number
320 - 231 = 89
89 ÷ 231 = 0.3852813852813853
0.3852813852813853 x 100 = 38.53%