-27.1% is the change from 321 to 234
Calculation steps:
[( 234 - 321 ) ÷ 321] x 100 = -27.1%
Formula
Percentage change = [(234 - 321) / 321] x 100
Subtract the new number by the original number
234 - 321 = -87
-87 ÷ 321 = -0.27102803738317754
-0.27102803738317754 x 100 = -27.1%