-16.88% is the change from 320 to 266
Calculation steps:
[( 266 - 320 ) ÷ 320] x 100 = -16.88%
Formula
Percentage change = [(266 - 320) / 320] x 100
Subtract the new number by the original number
266 - 320 = -54
-54 ÷ 320 = -0.16875
-0.16875 x 100 = -16.88%