BISMARCK, N.D. (AP) — Officials say North Dakota's oil tax savings account could more than double to $6 billion by 2017.

The Bismarck Tribune reports the fund's balance is $2.4 billion at present.

The Legacy Fund gets 30 percent of the state's oil tax collections. The money can't be touched before 2017 and it would still take a two-thirds vote of the Legislature for the state to dip into the fund.

North Dakota voters approved the fund in 2010. It received its first deposit of $34.3 million in September 2011.

A group called The Legacy Fund Initiative says the fund could swell to $230 billion by 2060 with strong investments.