-80% is the change from 815 to 163
Calculation steps:
[( 163 - 815 ) ÷ 815] x 100 = -80%
Formula
Percentage change = [(163 - 815) / 815] x 100
Subtract the new number by the original number
163 - 815 = -652
-652 ÷ 815 = -0.8
-0.8 x 100 = -80%
Example