2.41% is the change from 830 to 850
Calculation steps:
[( 850 - 830 ) ÷ 830] x 100 = 2.41%
Formula
Percentage change = [(850 - 830) / 830] x 100
Subtract the new number by the original number
850 - 830 = 20
20 ÷ 830 = 0.024096385542168676
0.024096385542168676 x 100 = 2.41%