-90.23% is the change from 819 to 80
Calculation steps:
[( 80 - 819 ) ÷ 819] x 100 = -90.23%
Formula
Percentage change = [(80 - 819) / 819] x 100
Subtract the new number by the original number
80 - 819 = -739
-739 ÷ 819 = -0.9023199023199023
-0.9023199023199023 x 100 = -90.23%