-65.85% is the change from 820 to 280
Calculation steps:
[( 280 - 820 ) ÷ 820] x 100 = -65.85%
Formula
Percentage change = [(280 - 820) / 820] x 100
Subtract the new number by the original number
280 - 820 = -540
-540 ÷ 820 = -0.6585365853658537
-0.6585365853658537 x 100 = -65.85%