-66.58% is the change from 766 to 256
Calculation steps:
[( 256 - 766 ) ÷ 766] x 100 = -66.58%
Formula
Percentage change = [(256 - 766) / 766] x 100
Subtract the new number by the original number
256 - 766 = -510
-510 ÷ 766 = -0.6657963446475196
-0.6657963446475196 x 100 = -66.58%