-9.35% is the change from 321 to 291
Calculation steps:
[( 291 - 321 ) ÷ 321] x 100 = -9.35%
Formula
Percentage change = [(291 - 321) / 321] x 100
Subtract the new number by the original number
291 - 321 = -30
-30 ÷ 321 = -0.09345794392523364
-0.09345794392523364 x 100 = -9.35%