-15.31% is the change from 980 to 830
Calculation steps:
[( 830 - 980 ) ÷ 980] x 100 = -15.31%
Formula
Percentage change = [(830 - 980) / 980] x 100
Subtract the new number by the original number
830 - 980 = -150
-150 ÷ 980 = -0.15306122448979592
-0.15306122448979592 x 100 = -15.31%