-90.91% is the change from 990 to 90
Calculation steps:
[( 90 - 990 ) ÷ 990] x 100 = -90.91%
Formula
Percentage change = [(90 - 990) / 990] x 100
Subtract the new number by the original number
90 - 990 = -900
-900 ÷ 990 = -0.9090909090909091
-0.9090909090909091 x 100 = -90.91%