Average in same measure in pivot table

[olgalopez]

Hi there!

I am using a pivot table to show the 'how many' from something sorting by diferent dimensions.

The problem comes when I'm trying to make a pivot table with the average of this count by months. I mean, the average of a month with the immediate before.

The expression I would like to do is this: (count(portfolio) + before(count(portfolio) /2) with no results. Actually I have the results I want but the issue is that in the first column it doesn't show properly the numbers because in the first column there are no 'before data'

It is something like that:

And when I expand the year it doesn't show data in the others years:

I've seen another problem and it is that if any dimension is moved, the expresion doesn't work.

Any idea to solve this? 

Thank you!