Dear Excel-Gurus,

Help is greatly appreciated. I have constructed a simplified verison of what I am attempting to do, and hopefully it will be straightforward.
In this example, I would like for my pivot table to automatically select the last 12 months of data that is available. That is, if my data for march would come in at the end of the month, I would like for the pivot table to add march 2016 to the pivot table, and take away (or not show) march from 2015.
I am hoping to able to just refresh this each month with a simple f9.

I have a feeling that define name could be of help, but I have not achieved to successfully add this by myself.
There will be many files such as this, so making it as automatic as possible will be necessary.

As stated, help will be appreciated, as I am stuck on this problem.

Many thanks.

Pivot auto update.xlsm