-7.06% is the change from 255 to 237
Calculation steps:
[( 237 - 255 ) ÷ 255] x 100 = -7.06%
Formula
Percentage change = [(237 - 255) / 255] x 100
Subtract the new number by the original number
237 - 255 = -18
-18 ÷ 255 = -0.07058823529411765
-0.07058823529411765 x 100 = -7.06%