1.22% is the change from 820 to 830
Calculation steps:
[( 830 - 820 ) ÷ 820] x 100 = 1.22%
Formula
Percentage change = [(830 - 820) / 820] x 100
Subtract the new number by the original number
830 - 820 = 10
10 ÷ 820 = 0.012195121951219513
0.012195121951219513 x 100 = 1.22%