-98.18% is the change from 990 to 18
Calculation steps:
[( 18 - 990 ) ÷ 990] x 100 = -98.18%
Formula
Percentage change = [(18 - 990) / 990] x 100
Subtract the new number by the original number
18 - 990 = -972
-972 ÷ 990 = -0.9818181818181818
-0.9818181818181818 x 100 = -98.18%