-16.86% is the change from 255 to 212
Calculation steps:
[( 212 - 255 ) ÷ 255] x 100 = -16.86%
Formula
Percentage change = [(212 - 255) / 255] x 100
Subtract the new number by the original number
212 - 255 = -43
-43 ÷ 255 = -0.16862745098039217
-0.16862745098039217 x 100 = -16.86%