U.S. oil production should be the main driver of growth outside members of the Organization of Petroleum Exporting Countries, the Energy Department said.

The Energy Information Administration said in a weekly status report non-OPEC supply growth outpaced global consumption in 2013 and should do so again in 2014.

EIA, the statistical arm of the Energy Department, said Wednesday it expects production from outside OPEC to increase by 1.5 million barrels per day this year and another 1.2 million bpd in 2015 "with production from tight oil formations in the United States as the main driver."

In its monthly market report, published Tuesday, EIA said it estimated U.S. oil production in May averaged 8.4 million bpd, the highest monthly average in a quarter century.

U.S. oil production for 2014 should average 8.4 million bpd and reach 9.3 million next year, which would represent the highest annual average since 1971 if EIA forecasts are accurate.

The increase in U.S. oil production means the U.S. economy is relying less on foreign oil resources.

For the week ending June 6, EIA said crude oil imports averaged 7.1 million bpd, up 23,000 bpd from the previous week. Nevertheless, over the last four weeks, crude oil imports were down 8.1 percent year-on-year.