-8.98% is the change from 857 to 780
Calculation steps:
[( 780 - 857 ) ÷ 857] x 100 = -8.98%
Formula
Percentage change = [(780 - 857) / 857] x 100
Subtract the new number by the original number
780 - 857 = -77
-77 ÷ 857 = -0.08984830805134189
-0.08984830805134189 x 100 = -8.98%