-98.44% is the change from 831 to 13
Calculation steps:
[( 13 - 831 ) ÷ 831] x 100 = -98.44%
Formula
Percentage change = [(13 - 831) / 831] x 100
Subtract the new number by the original number
13 - 831 = -818
-818 ÷ 831 = -0.9843561973525873
-0.9843561973525873 x 100 = -98.44%