-89.87% is the change from 839 to 85
Calculation steps:
[( 85 - 839 ) ÷ 839] x 100 = -89.87%
Formula
Percentage change = [(85 - 839) / 839] x 100
Subtract the new number by the original number
85 - 839 = -754
-754 ÷ 839 = -0.8986889153754469
-0.8986889153754469 x 100 = -89.87%