-80% is the change from 820 to 164
Calculation steps:
[( 164 - 820 ) ÷ 820] x 100 = -80%
Formula
Percentage change = [(164 - 820) / 820] x 100
Subtract the new number by the original number
164 - 820 = -656
-656 ÷ 820 = -0.8
-0.8 x 100 = -80%
Example