-16.44% is the change from 821 to 686
Calculation steps:
[( 686 - 821 ) ÷ 821] x 100 = -16.44%
Formula
Percentage change = [(686 - 821) / 821] x 100
Subtract the new number by the original number
686 - 821 = -135
-135 ÷ 821 = -0.16443361753958588
-0.16443361753958588 x 100 = -16.44%