100% is the change from 343 to 686
Calculation steps:
[( 686 - 343 ) ÷ 343] x 100 = 100%
Formula
Percentage change = [(686 - 343) / 343] x 100
Subtract the new number by the original number
686 - 343 = 343
343 ÷ 343 = 1
1 x 100 = 100%
Example