-95.33% is the change from 321 to 15
Calculation steps:
[( 15 - 321 ) ÷ 321] x 100 = -95.33%
Formula
Percentage change = [(15 - 321) / 321] x 100
Subtract the new number by the original number
15 - 321 = -306
-306 ÷ 321 = -0.9532710280373832
-0.9532710280373832 x 100 = -95.33%