-16.02% is the change from 256 to 215
Calculation steps:
[( 215 - 256 ) ÷ 256] x 100 = -16.02%
Formula
Percentage change = [(215 - 256) / 256] x 100
Subtract the new number by the original number
215 - 256 = -41
-41 ÷ 256 = -0.16015625
-0.16015625 x 100 = -16.02%