-80.98% is the change from 820 to 156
Calculation steps:
[( 156 - 820 ) ÷ 820] x 100 = -80.98%
Formula
Percentage change = [(156 - 820) / 820] x 100
Subtract the new number by the original number
156 - 820 = -664
-664 ÷ 820 = -0.8097560975609757
-0.8097560975609757 x 100 = -80.98%