-50.19% is the change from 257 to 128
Calculation steps:
[( 128 - 257 ) ÷ 257] x 100 = -50.19%
Formula
Percentage change = [(128 - 257) / 257] x 100
Subtract the new number by the original number
128 - 257 = -129
-129 ÷ 257 = -0.5019455252918288
-0.5019455252918288 x 100 = -50.19%