-81.71% is the change from 820 to 150
Calculation steps:
[( 150 - 820 ) ÷ 820] x 100 = -81.71%
Formula
Percentage change = [(150 - 820) / 820] x 100
Subtract the new number by the original number
150 - 820 = -670
-670 ÷ 820 = -0.8170731707317073
-0.8170731707317073 x 100 = -81.71%