-8.69% is the change from 909 to 830
Calculation steps:
[( 830 - 909 ) ÷ 909] x 100 = -8.69%
Formula
Percentage change = [(830 - 909) / 909] x 100
Subtract the new number by the original number
830 - 909 = -79
-79 ÷ 909 = -0.08690869086908691
-0.08690869086908691 x 100 = -8.69%