-90.78% is the change from 857 to 79
Calculation steps:
[( 79 - 857 ) ÷ 857] x 100 = -90.78%
Formula
Percentage change = [(79 - 857) / 857] x 100
Subtract the new number by the original number
79 - 857 = -778
-778 ÷ 857 = -0.9078179696616102
-0.9078179696616102 x 100 = -90.78%