So, who actually has been stealing Iraq's oil?

What with Obama’s announcement today that he’s withdrawing all US troops from Iraq by the end of the year, it seemed like a good time to ask.

I mean, has the US been stealing it all along? And is still? Or is it that all of the western-affiliated nations have their hands in the till? Or has their only ever been the “normal” corruption prevalent there as established by Saddam in the first place?