30.77% is the change from 39 to 51
Calculation steps:
[( 51 - 39 ) ÷ 39] x 100 = 30.77%
Formula
Percentage change = [(51 - 39) / 39] x 100
Subtract the new number by the original number
51 - 39 = 12
12 ÷ 39 = 0.3076923076923077
0.3076923076923077 x 100 = 30.77%