-84.64% is the change from 521 to 80
Calculation steps:
[( 80 - 521 ) ÷ 521] x 100 = -84.64%
Formula
Percentage change = [(80 - 521) / 521] x 100
Subtract the new number by the original number
80 - 521 = -441
-441 ÷ 521 = -0.8464491362763915
-0.8464491362763915 x 100 = -84.64%