8.45% is the change from 213 to 231
Calculation steps:
[( 231 - 213 ) ÷ 213] x 100 = 8.45%
Formula
Percentage change = [(231 - 213) / 213] x 100
Subtract the new number by the original number
231 - 213 = 18
18 ÷ 213 = 0.08450704225352113
0.08450704225352113 x 100 = 8.45%