-86.84% is the change from 646 to 85
Calculation steps:
[( 85 - 646 ) ÷ 646] x 100 = -86.84%
Formula
Percentage change = [(85 - 646) / 646] x 100
Subtract the new number by the original number
85 - 646 = -561
-561 ÷ 646 = -0.868421052631579
-0.868421052631579 x 100 = -86.84%