The headline is a bit involved... I have 12 months' worth of expense reports:
12 tables (one table per month) with a list of transactions, ordered by date, category, subcategory & amount.

I want to see the total amounts relating to each payment subcategory.
I already have a pivot table for each table, summarizing the totals per sub-category, but I want another table that summarizes all 12 transaction tables into one pivot table.
I.e. I want one pivot table that shows the total amount spent on each subcategory for each month.

I want this in order to do a line graph analysis to see how totals spent on each subcategory has fluctuated over the year.

If anyone can give tips for either the consolidated pivot table or the line graph afterwards, or both, I would appreciate it a lot!!