3.39% is the change from 619 to 640
Calculation steps:
[( 640 - 619 ) ÷ 619] x 100 = 3.39%
Formula
Percentage change = [(640 - 619) / 619] x 100
Subtract the new number by the original number
640 - 619 = 21
21 ÷ 619 = 0.033925686591276254
0.033925686591276254 x 100 = 3.39%