U.S. imports of natural gas are at their lowest levels in two decades, the U.S. Energy Information Administration said. Net imports, which the EIA defined as imports minus exports, for 2011 were slightly more than 5 billion cubic feet per day in 2011, the lowest level since 1992. The EIA said the decline in net imports was because of lower overall imports and because of higher exports. The agency said net imports have declined at a steady pace since 2007. Imports in general have been lower this year, though much of that was attributed to a significantly warmer-than-average spring in the United States. The United States has some of the richest deposits of natural gas in the world. The White House this week, in a progress report on its energy policy, said oil and natural gas production was at peak levels. White House critics, however, said much of that production increase was because of policies enacted by the previous administration.