-98.64% is the change from 663 to 9
Calculation steps:
[( 9 - 663 ) ÷ 663] x 100 = -98.64%
Formula
Percentage change = [(9 - 663) / 663] x 100
Subtract the new number by the original number
9 - 663 = -654
-654 ÷ 663 = -0.9864253393665159
-0.9864253393665159 x 100 = -98.64%