52week rolling period

[#1]

Hi all,

I am trying to create a pivot table containing a 52 week rolling period. I already made a start in the added file containing a rolling period of 4 weeks. But I can't get it to work.  (Amount of used trucks are not used the file)

The formula needs to show me:

Average km per week:'Total km per week / total trucks used that week'. And then the total of 52 week averages.

For example when 1-1-2014 starts I want it to show me the total of all calculations of the last 52 weeks.

Example:

Week

2014-1 shows week 2013-1 up to 2013-52

2014-2 shows week 2013-2 up to 2014-1

2014-3 shows week 2013-3 up to 2014-2

etc etc.

I hope someone can help me with this problem!!

Kind regards,

Vincent