50.59% is the change from 340 to 512
Calculation steps:
[( 512 - 340 ) ÷ 340] x 100 = 50.59%
Formula
Percentage change = [(512 - 340) / 340] x 100
Subtract the new number by the original number
512 - 340 = 172
172 ÷ 340 = 0.5058823529411764
0.5058823529411764 x 100 = 50.59%