71.28% is the change from 390 to 668
Calculation steps:
[( 668 - 390 ) ÷ 390] x 100 = 71.28%
Formula
Percentage change = [(668 - 390) / 390] x 100
Subtract the new number by the original number
668 - 390 = 278
278 ÷ 390 = 0.7128205128205128
0.7128205128205128 x 100 = 71.28%