-98.99% is the change from 990 to 10
Calculation steps:
[( 10 - 990 ) ÷ 990] x 100 = -98.99%
Formula
Percentage change = [(10 - 990) / 990] x 100
Subtract the new number by the original number
10 - 990 = -980
-980 ÷ 990 = -0.98989898989899
-0.98989898989899 x 100 = -98.99%