23.75% is the change from 421 to 521
Calculation steps:
[( 521 - 421 ) ÷ 421] x 100 = 23.75%
Formula
Percentage change = [(521 - 421) / 421] x 100
Subtract the new number by the original number
521 - 421 = 100
100 ÷ 421 = 0.2375296912114014
0.2375296912114014 x 100 = 23.75%