-23.08% is the change from 39 to 30
Calculation steps:
[( 30 - 39 ) ÷ 39] x 100 = -23.08%
Formula
Percentage change = [(30 - 39) / 39] x 100
Subtract the new number by the original number
30 - 39 = -9
-9 ÷ 39 = -0.23076923076923078
-0.23076923076923078 x 100 = -23.08%