2.82% is the change from 639 to 657
Calculation steps:
[( 657 - 639 ) ÷ 639] x 100 = 2.82%
Formula
Percentage change = [(657 - 639) / 639] x 100
Subtract the new number by the original number
657 - 639 = 18
18 ÷ 639 = 0.028169014084507043
0.028169014084507043 x 100 = 2.82%