-98.55% is the change from 830 to 12
Calculation steps:
[( 12 - 830 ) ÷ 830] x 100 = -98.55%
Formula
Percentage change = [(12 - 830) / 830] x 100
Subtract the new number by the original number
12 - 830 = -818
-818 ÷ 830 = -0.9855421686746988
-0.9855421686746988 x 100 = -98.55%