-86.78% is the change from 643 to 85
Calculation steps:
[( 85 - 643 ) ÷ 643] x 100 = -86.78%
Formula
Percentage change = [(85 - 643) / 643] x 100
Subtract the new number by the original number
85 - 643 = -558
-558 ÷ 643 = -0.8678071539657853
-0.8678071539657853 x 100 = -86.78%