BISMARCK, N.D. (AP) — Conservation advocates who want to set aside a bigger slice of North Dakota's oil revenues for an outdoor heritage fund have taken the next step toward bringing the idea to a public vote.

The Forum reports backers of the proposed Clean Water, Wildlife and Parks Fund have filed a proposed petition with Secretary of State Al Jaeger.

Jaeger must approve it for circulation. He and Attorney General Wayne Stenehjem then would draft a petition title — a short summary that fairly represents the proposal. Advocates then would need to collect 26,904 valid signatures to get the measure on the November 2014 ballot.

The measure would set aside 5 percent of the state's oil extraction tax revenue, which would raise an estimated $150 million during the 2013-15 budget period.