2.21% is the change from 813 to 831
Calculation steps:
[( 831 - 813 ) ÷ 813] x 100 = 2.21%
Formula
Percentage change = [(831 - 813) / 813] x 100
Subtract the new number by the original number
831 - 813 = 18
18 ÷ 813 = 0.02214022140221402
0.02214022140221402 x 100 = 2.21%