Pivot Chart - Mean Line

[*shudder*]

Hi Guys,

I have been searching around for an answer to this for a couple of hours and struggling to find a solution.

I would like to add a dynamic mean line into a pivot table/chart dependent on which department and month I am looking at.

Source data is set out like this where I have a formula to calculate the average:

Name	Dept	Month	Volume	Average
One	AA	January	10	25
Two	AA	January	15	25
Three	AA	January	50	25
Four	BB	January	20	73
Five	BB	January	50	73
Six	BB	January	150	73
One	AA	February	15	15
Two	AA	February	10	15
Three	AA	February	20	15
Four	BB	February	30	40
Five	BB	February	40	40
Six	BB	February	50	40

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</tbody>

With the pivot table data currently looking like this with slicers for Name, Department and Month:

Name	Volume	Average
One	10	25
Two	15	25
Three	12	25
Four	20	73
Five	50	73
Six	150	73

<tbody>
</tbody>

What I would like the pivot table to do is adjust theaverage/mean dependant on which slicer items are selected i.e.

Slicer Selections
Dept: AA
Month: January
Name: One, Two

Pivot would show

Name	Volume	Average
One	10	12.5
Two	15	12.5

<tbody>
</tbody>

Thanks in advance

Stuart