6.68% is the change from 599 to 639
Calculation steps:
[( 639 - 599 ) ÷ 599] x 100 = 6.68%
Formula
Percentage change = [(639 - 599) / 599] x 100
Subtract the new number by the original number
639 - 599 = 40
40 ÷ 599 = 0.0667779632721202
0.0667779632721202 x 100 = 6.68%