287.11% is the change from 256 to 991
Calculation steps:
[( 991 - 256 ) ÷ 256] x 100 = 287.11%
Formula
Percentage change = [(991 - 256) / 256] x 100
Subtract the new number by the original number
991 - 256 = 735
735 ÷ 256 = 2.87109375
2.87109375 x 100 = 287.11%