2.5% is the change from 639 to 655
Calculation steps:
[( 655 - 639 ) ÷ 639] x 100 = 2.5%
Formula
Percentage change = [(655 - 639) / 639] x 100
Subtract the new number by the original number
655 - 639 = 16
16 ÷ 639 = 0.025039123630672927
0.025039123630672927 x 100 = 2.5%