-87.1% is the change from 620 to 80
Calculation steps:
[( 80 - 620 ) ÷ 620] x 100 = -87.1%
Formula
Percentage change = [(80 - 620) / 620] x 100
Subtract the new number by the original number
80 - 620 = -540
-540 ÷ 620 = -0.8709677419354839
-0.8709677419354839 x 100 = -87.1%