21.14% is the change from 686 to 831
Calculation steps:
[( 831 - 686 ) ÷ 686] x 100 = 21.14%
Formula
Percentage change = [(831 - 686) / 686] x 100
Subtract the new number by the original number
831 - 686 = 145
145 ÷ 686 = 0.21137026239067055
0.21137026239067055 x 100 = 21.14%