-64.84% is the change from 256 to 90
Calculation steps:
[( 90 - 256 ) ÷ 256] x 100 = -64.84%
Formula
Percentage change = [(90 - 256) / 256] x 100
Subtract the new number by the original number
90 - 256 = -166
-166 ÷ 256 = -0.6484375
-0.6484375 x 100 = -64.84%