-5.56% is the change from 270 to 255
Calculation steps:
[( 255 - 270 ) ÷ 270] x 100 = -5.56%
Formula
Percentage change = [(255 - 270) / 270] x 100
Subtract the new number by the original number
255 - 270 = -15
-15 ÷ 270 = -0.05555555555555555
-0.05555555555555555 x 100 = -5.56%