The problem seems to be that most of it seems to have been spent on foreign contractors, with minimal results in terms of rebuilding infrastructure, improving health care or funding reconstruction by Iraqi businesses.
With 96% of the economy based on oil, that means 96% of the people get their livelihood from the oil money. Since there are 25 million people and an 875 dollar a year per capita standard of living if the people use ALL of that money, then that doesn't leave much for anything else, does it?
How much a year do you think each of those people should have to live on?
How much is the per capita for an American citizen?