-61.21% is the change from 660 to 256
Calculation steps:
[( 256 - 660 ) ÷ 660] x 100 = -61.21%
Formula
Percentage change = [(256 - 660) / 660] x 100
Subtract the new number by the original number
256 - 660 = -404
-404 ÷ 660 = -0.6121212121212121
-0.6121212121212121 x 100 = -61.21%