138.3% is the change from 342 to 815
Calculation steps:
[( 815 - 342 ) ÷ 342] x 100 = 138.3%
Formula
Percentage change = [(815 - 342) / 342] x 100
Subtract the new number by the original number
815 - 342 = 473
473 ÷ 342 = 1.3830409356725146
1.3830409356725146 x 100 = 138.3%