-83.2% is the change from 506 to 85
Calculation steps:
[( 85 - 506 ) ÷ 506] x 100 = -83.2%
Formula
Percentage change = [(85 - 506) / 506] x 100
Subtract the new number by the original number
85 - 506 = -421
-421 ÷ 506 = -0.8320158102766798
-0.8320158102766798 x 100 = -83.2%