Oil remains the lifeblood of any war effort today and drives many components of the modern military complex including aircraft, vehicles, warships, small arms, and general industry. For the purposes of the GFP ranking, oil consumption is applied as a penalty to each nation, the higher its consumption the worse effect on a theoretical war effort. Oil consumption can be offset by the oil production value and this is factored in along with a given nation's proven oil reserves Data presented on this list is through 2018. Values are presented in bbl/day (Barrels Per Day). Estimates are made when official data is not available.