-24.5% is the change from 857 to 647
Calculation steps:
[( 647 - 857 ) ÷ 857] x 100 = -24.5%
Formula
Percentage change = [(647 - 857) / 857] x 100
Subtract the new number by the original number
647 - 857 = -210
-210 ÷ 857 = -0.24504084014002334
-0.24504084014002334 x 100 = -24.5%