HOUSTON, June 6 (Xinhua) -- Working gas storage in the contiguous United States was 1,986 billion cubic feet (about 56.24 billion cubic meters) in the week ending May 31, a net increase of 119 billion cubic feet, or 6.4 percent, from the previous week, the U.S. Energy Information Administration (EIA) said in a report on Thursday.

The total working gas storage increased by 10.1 percent from this time last year, or 10.8 percent below the five-year average, but still within the five-year historical range, according to the EIA's Weekly Natural Gas Storage Report.

The storage of working gas usually turns to increase in late April and will continue to grow in early November when heating season starts in the country, according to previous data.

Working gas is defined as the amount of natural gas stored underground that can be withdrawn for use. Its storage capacity can be measured in two ways: design capacity and demonstrated maximum working gas capacity.

The contiguous United States consists of the 48 adjoining states of the United States, plus the District of Columbia, and excludes the non-contiguous states of Alaska and Hawaii, and all off-shore insular areas.