-0.25% is the change from 401 to 400
Calculation steps:
[( 400 - 401 ) ÷ 401] x 100 = -0.25%
Formula
Percentage change = [(400 - 401) / 401] x 100
Subtract the new number by the original number
400 - 401 = -1
-1 ÷ 401 = -0.0024937655860349127
-0.0024937655860349127 x 100 = -0.25%