-21.82% is the change from 857 to 670
Calculation steps:
[( 670 - 857 ) ÷ 857] x 100 = -21.82%
Formula
Percentage change = [(670 - 857) / 857] x 100
Subtract the new number by the original number
670 - 857 = -187
-187 ÷ 857 = -0.21820303383897316
-0.21820303383897316 x 100 = -21.82%