If you're like most investors, you probably know that the world's largest oil producer is Saudi Arabia. In 2005, Saudi Arabia churned out more than 11 million barrels of oil per day, roughly 13.5 percent of the world's total supply.


And you may have guessed the world's second-largest producer: the Russian Federation. In 2005, Russia chipped in about 9.5 million barrels per day, a bit more than 12 percent of the total global production.

But guessing the world's third-largest producer is more of a challenge. If you guessed Nigeria, Venezuela, Iraq, Iran, the United Kingdom or Canada, you're incorrect. The third-largest oil producer in the world is the US. The US produced 6.8 million barrels of oil per day in 2005, edging out Iran by more than 2.75 million barrels per day.