-87.12% is the change from 660 to 85
Calculation steps:
[( 85 - 660 ) ÷ 660] x 100 = -87.12%
Formula
Percentage change = [(85 - 660) / 660] x 100
Subtract the new number by the original number
85 - 660 = -575
-575 ÷ 660 = -0.8712121212121212
-0.8712121212121212 x 100 = -87.12%