Using AllPrevious with exception of first value

I am trying to sum values with the exception of the very first value.  Is there a way to do this?  I currently have this which includes the first value. 

 [Hits per code (count)] THEN Sum(([Value] / Avg([Value])) - 1) OVER (AllPrevious([Axis.X])) as [INL] 


How can I perfor the equation on n=1:n-1?  



(3) Answers