97.15% is the change from 421 to 830
Calculation steps:
[( 830 - 421 ) ÷ 421] x 100 = 97.15%
Formula
Percentage change = [(830 - 421) / 421] x 100
Subtract the new number by the original number
830 - 421 = 409
409 ÷ 421 = 0.9714964370546318
0.9714964370546318 x 100 = 97.15%