-20.83% is the change from 821 to 650
Calculation steps:
[( 650 - 821 ) ÷ 821] x 100 = -20.83%
Formula
Percentage change = [(650 - 821) / 821] x 100
Subtract the new number by the original number
650 - 821 = -171
-171 ÷ 821 = -0.20828258221680876
-0.20828258221680876 x 100 = -20.83%