-19.95% is the change from 857 to 686
Calculation steps:
[( 686 - 857 ) ÷ 857] x 100 = -19.95%
Formula
Percentage change = [(686 - 857) / 857] x 100
Subtract the new number by the original number
686 - 857 = -171
-171 ÷ 857 = -0.19953325554259044
-0.19953325554259044 x 100 = -19.95%