23.99% is the change from 521 to 646
Calculation steps:
[( 646 - 521 ) ÷ 521] x 100 = 23.99%
Formula
Percentage change = [(646 - 521) / 521] x 100
Subtract the new number by the original number
646 - 521 = 125
125 ÷ 521 = 0.2399232245681382
0.2399232245681382 x 100 = 23.99%