40.59% is the change from 340 to 478
Calculation steps:
[( 478 - 340 ) ÷ 340] x 100 = 40.59%
Formula
Percentage change = [(478 - 340) / 340] x 100
Subtract the new number by the original number
478 - 340 = 138
138 ÷ 340 = 0.40588235294117647
0.40588235294117647 x 100 = 40.59%