You can get Order Reports from Amazon, listing all the physical goods you've bought since you first signed up. (Weirdly, they don't have the same for electronic fulfillment.) They'll make you a big ol' CSV file that you can drag into a spreadsheet.
But I hate spreadsheets, so I made up the Amazon Adder that lets you copy and paste the whole CSV into a textfield (I didn't want to get involved with people sending any information to my server)
Anyway, the page makes that chart, breaks down by year, month of year, and then by category, with each category getting a list of the actual items bought.
Now what to do with all these damn cardboard boxes...