-90.2% is the change from 990 to 97
Calculation steps:
[( 97 - 990 ) ÷ 990] x 100 = -90.2%
Formula
Percentage change = [(97 - 990) / 990] x 100
Subtract the new number by the original number
97 - 990 = -893
-893 ÷ 990 = -0.902020202020202
-0.902020202020202 x 100 = -90.2%