-83.65% is the change from 520 to 85
Calculation steps:
[( 85 - 520 ) ÷ 520] x 100 = -83.65%
Formula
Percentage change = [(85 - 520) / 520] x 100
Subtract the new number by the original number
85 - 520 = -435
-435 ÷ 520 = -0.8365384615384616
-0.8365384615384616 x 100 = -83.65%