23.1% is the change from 342 to 421
Calculation steps:
[( 421 - 342 ) ÷ 342] x 100 = 23.1%
Formula
Percentage change = [(421 - 342) / 342] x 100
Subtract the new number by the original number
421 - 342 = 79
79 ÷ 342 = 0.2309941520467836
0.2309941520467836 x 100 = 23.1%