An earlier estimate from the US Energy Information Administration (EIA) was even larger, at 36 trillion cubic meters.

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European Union countries accounted for 18 percent of Iranian crude oil sales in that period, the US Energy Information Administration (EIA) also said.

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But if you look at data from the US Energy Information Administration (EIA) you get a much different picture, one in which Saudi Arabia currently produces about 1.2 million barrels a day more than Russia.

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Shale gas also helps to explain the sharp drop in US oil imports forecast by the EIA in the next two years.

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