-71.43% is the change from 280 to 80
Calculation steps:
[( 80 - 280 ) ÷ 280] x 100 = -71.43%
Formula
Percentage change = [(80 - 280) / 280] x 100
Subtract the new number by the original number
80 - 280 = -200
-200 ÷ 280 = -0.7142857142857143
-0.7142857142857143 x 100 = -71.43%