-28.75% is the change from 320 to 228
Calculation steps:
[( 228 - 320 ) ÷ 320] x 100 = -28.75%
Formula
Percentage change = [(228 - 320) / 320] x 100
Subtract the new number by the original number
228 - 320 = -92
-92 ÷ 320 = -0.2875
-0.2875 x 100 = -28.75%