-69.16% is the change from 321 to 99
Calculation steps:
[( 99 - 321 ) ÷ 321] x 100 = -69.16%
Formula
Percentage change = [(99 - 321) / 321] x 100
Subtract the new number by the original number
99 - 321 = -222
-222 ÷ 321 = -0.6915887850467289
-0.6915887850467289 x 100 = -69.16%