-22.29% is the change from 857 to 666
Calculation steps:
[( 666 - 857 ) ÷ 857] x 100 = -22.29%
Formula
Percentage change = [(666 - 857) / 857] x 100
Subtract the new number by the original number
666 - 857 = -191
-191 ÷ 857 = -0.22287047841306884
-0.22287047841306884 x 100 = -22.29%