21.73% is the change from 428 to 521
Calculation steps:
[( 521 - 428 ) ÷ 428] x 100 = 21.73%
Formula
Percentage change = [(521 - 428) / 428] x 100
Subtract the new number by the original number
521 - 428 = 93
93 ÷ 428 = 0.21728971962616822
0.21728971962616822 x 100 = 21.73%