28.57% is the change from 7 to 9
Calculation steps:
[( 9 - 7 ) ÷ 7] x 100 = 28.57%
Formula
Percentage change = [(9 - 7) / 7] x 100
Subtract the new number by the original number
9 - 7 = 2
2 ÷ 7 = 0.2857142857142857
0.2857142857142857 x 100 = 28.57%
Example