30.95% is the change from 391 to 512
Calculation steps:
[( 512 - 391 ) ÷ 391] x 100 = 30.95%
Formula
Percentage change = [(512 - 391) / 391] x 100
Subtract the new number by the original number
512 - 391 = 121
121 ÷ 391 = 0.309462915601023
0.309462915601023 x 100 = 30.95%