71.5% is the change from 400 to 686
Calculation steps:
[( 686 - 400 ) ÷ 400] x 100 = 71.5%
Formula
Percentage change = [(686 - 400) / 400] x 100
Subtract the new number by the original number
686 - 400 = 286
286 ÷ 400 = 0.715
0.715 x 100 = 71.5%
Example