21.74% is the change from 345 to 420
Calculation steps:
[( 420 - 345 ) ÷ 345] x 100 = 21.74%
Formula
Percentage change = [(420 - 345) / 345] x 100
Subtract the new number by the original number
420 - 345 = 75
75 ÷ 345 = 0.21739130434782608
0.21739130434782608 x 100 = 21.74%