Show collective average and item total in one graph

Show collective average and item total in one graph

I have query that would like some help.
I have a table where each row shows the monthly total of 15 items. 
I would like to show in a graph the average of all and compare that to the individual monthly total. 
The individual monthly item, I would like the end user to be able to select.

I have created an aggregate formulae to show the average, however when that is compared to the total and filter is applied, this changes for both. I would like the average of all items to remain static and the monthly total of each item to be dynamic.

Thank you for the help on this in advance.