-97.1% is the change from 620 to 18
Calculation steps:
[( 18 - 620 ) ÷ 620] x 100 = -97.1%
Formula
Percentage change = [(18 - 620) / 620] x 100
Subtract the new number by the original number
18 - 620 = -602
-602 ÷ 620 = -0.9709677419354839
-0.9709677419354839 x 100 = -97.1%