-3.43% is the change from 321 to 310
Calculation steps:
[( 310 - 321 ) ÷ 321] x 100 = -3.43%
Formula
Percentage change = [(310 - 321) / 321] x 100
Subtract the new number by the original number
310 - 321 = -11
-11 ÷ 321 = -0.03426791277258567
-0.03426791277258567 x 100 = -3.43%