-82.94% is the change from 815 to 139
Calculation steps:
[( 139 - 815 ) ÷ 815] x 100 = -82.94%
Formula
Percentage change = [(139 - 815) / 815] x 100
Subtract the new number by the original number
139 - 815 = -676
-676 ÷ 815 = -0.8294478527607362
-0.8294478527607362 x 100 = -82.94%