31.67% is the change from 521 to 686
Calculation steps:
[( 686 - 521 ) ÷ 521] x 100 = 31.67%
Formula
Percentage change = [(686 - 521) / 521] x 100
Subtract the new number by the original number
686 - 521 = 165
165 ÷ 521 = 0.31669865642994244
0.31669865642994244 x 100 = 31.67%