21.14% is the change from 421 to 510
Calculation steps:
[( 510 - 421 ) ÷ 421] x 100 = 21.14%
Formula
Percentage change = [(510 - 421) / 421] x 100
Subtract the new number by the original number
510 - 421 = 89
89 ÷ 421 = 0.21140142517814728
0.21140142517814728 x 100 = 21.14%