-72.9% is the change from 321 to 87
Calculation steps:
[( 87 - 321 ) ÷ 321] x 100 = -72.9%
Formula
Percentage change = [(87 - 321) / 321] x 100
Subtract the new number by the original number
87 - 321 = -234
-234 ÷ 321 = -0.7289719626168224
-0.7289719626168224 x 100 = -72.9%