-0.4% is the change from 251 to 250
Calculation steps:
[( 250 - 251 ) ÷ 251] x 100 = -0.4%
Formula
Percentage change = [(250 - 251) / 251] x 100
Subtract the new number by the original number
250 - 251 = -1
-1 ÷ 251 = -0.00398406374501992
-0.00398406374501992 x 100 = -0.4%