-89.38% is the change from 857 to 91
Calculation steps:
[( 91 - 857 ) ÷ 857] x 100 = -89.38%
Formula
Percentage change = [(91 - 857) / 857] x 100
Subtract the new number by the original number
91 - 857 = -766
-766 ÷ 857 = -0.8938156359393232
-0.8938156359393232 x 100 = -89.38%