-99.18% is the change from 857 to 7
Calculation steps:
[( 7 - 857 ) ÷ 857] x 100 = -99.18%
Formula
Percentage change = [(7 - 857) / 857] x 100
Subtract the new number by the original number
7 - 857 = -850
-850 ÷ 857 = -0.9918319719953326
-0.9918319719953326 x 100 = -99.18%