-84.91% is the change from 815 to 123
Calculation steps:
[( 123 - 815 ) ÷ 815] x 100 = -84.91%
Formula
Percentage change = [(123 - 815) / 815] x 100
Subtract the new number by the original number
123 - 815 = -692
-692 ÷ 815 = -0.849079754601227
-0.849079754601227 x 100 = -84.91%