68.8% is the change from 391 to 660
Calculation steps:
[( 660 - 391 ) ÷ 391] x 100 = 68.8%
Formula
Percentage change = [(660 - 391) / 391] x 100
Subtract the new number by the original number
660 - 391 = 269
269 ÷ 391 = 0.6879795396419437
0.6879795396419437 x 100 = 68.8%