-97.93% is the change from 821 to 17
Calculation steps:
[( 17 - 821 ) ÷ 821] x 100 = -97.93%
Formula
Percentage change = [(17 - 821) / 821] x 100
Subtract the new number by the original number
17 - 821 = -804
-804 ÷ 821 = -0.9792935444579781
-0.9792935444579781 x 100 = -97.93%