-79.65% is the change from 850 to 173
Calculation steps:
[( 173 - 850 ) ÷ 850] x 100 = -79.65%
Formula
Percentage change = [(173 - 850) / 850] x 100
Subtract the new number by the original number
173 - 850 = -677
-677 ÷ 850 = -0.7964705882352942
-0.7964705882352942 x 100 = -79.65%