31.75% is the change from 630 to 830
Calculation steps:
[( 830 - 630 ) ÷ 630] x 100 = 31.75%
Formula
Percentage change = [(830 - 630) / 630] x 100
Subtract the new number by the original number
830 - 630 = 200
200 ÷ 630 = 0.31746031746031744
0.31746031746031744 x 100 = 31.75%