2.47% is the change from 810 to 830
Calculation steps:
[( 830 - 810 ) ÷ 810] x 100 = 2.47%
Formula
Percentage change = [(830 - 810) / 810] x 100
Subtract the new number by the original number
830 - 810 = 20
20 ÷ 810 = 0.024691358024691357
0.024691358024691357 x 100 = 2.47%