-15.31% is the change from 320 to 271
Calculation steps:
[( 271 - 320 ) ÷ 320] x 100 = -15.31%
Formula
Percentage change = [(271 - 320) / 320] x 100
Subtract the new number by the original number
271 - 320 = -49
-49 ÷ 320 = -0.153125
-0.153125 x 100 = -15.31%