0.31% is the change from 639 to 641
Calculation steps:
[( 641 - 639 ) ÷ 639] x 100 = 0.31%
Formula
Percentage change = [(641 - 639) / 639] x 100
Subtract the new number by the original number
641 - 639 = 2
2 ÷ 639 = 0.003129890453834116
0.003129890453834116 x 100 = 0.31%