That is a pretty graph.
Maybe I should put my recorded pictures into something similar.

When I styarted in late 2000, it was everything I could get my hands on - generally locally since I didn't have a card. When I got the card in 2001, there were many many lean weeks when I poured cash into the card to import, while also getting stuff locally - anything and everything

That was the patern until mid run Energon when I decided that I couldn't actually afford, nor store them. So I decided to ditch collecting the American lines and focus on Japanese, unless there was no Japanese version (or it was a USA Edition)

In 2006 I changed my mind again, and again in 2009 - I sold mostly all the stuff that was't related to G1/G2/e-Hobby/Binaltech/Alternators/Classics/Universe/Henkei.

This year I have only imported a few things, with the plan to pick what I have missed while on holiday in Singapore. Have learnt its a heck of a lot cheaper over there.