-97.79% is the change from 815 to 18
Calculation steps:
[( 18 - 815 ) ÷ 815] x 100 = -97.79%
Formula
Percentage change = [(18 - 815) / 815] x 100
Subtract the new number by the original number
18 - 815 = -797
-797 ÷ 815 = -0.9779141104294479
-0.9779141104294479 x 100 = -97.79%