-99.02% is the change from 815 to 8
Calculation steps:
[( 8 - 815 ) ÷ 815] x 100 = -99.02%
Formula
Percentage change = [(8 - 815) / 815] x 100
Subtract the new number by the original number
8 - 815 = -807
-807 ÷ 815 = -0.9901840490797545
-0.9901840490797545 x 100 = -99.02%