-97.2% is the change from 321 to 9
Calculation steps:
[( 9 - 321 ) ÷ 321] x 100 = -97.2%
Formula
Percentage change = [(9 - 321) / 321] x 100
Subtract the new number by the original number
9 - 321 = -312
-312 ÷ 321 = -0.9719626168224299
-0.9719626168224299 x 100 = -97.2%