0.31% is the change from 643 to 645
Calculation steps:
[( 645 - 643 ) ÷ 643] x 100 = 0.31%
Formula
Percentage change = [(645 - 643) / 643] x 100
Subtract the new number by the original number
645 - 643 = 2
2 ÷ 643 = 0.003110419906687403
0.003110419906687403 x 100 = 0.31%