2.56% is the change from 39 to 40
Calculation steps:
[( 40 - 39 ) ÷ 39] x 100 = 2.56%
Formula
Percentage change = [(40 - 39) / 39] x 100
Subtract the new number by the original number
40 - 39 = 1
1 ÷ 39 = 0.02564102564102564
0.02564102564102564 x 100 = 2.56%