OKLAHOMA CITY (AP) - Oklahoma is now third in the nation in the number of slot machines in the state, according to a study of the gaming industry nationwide, and Oklahomans spent an average of more than $600 per capita to gamble.

The 597-page study illustrates Oklahoma's development as a gambling state since November 2004, when voters approved expanded casino gaming and a lottery.

It found Oklahoma has a slot machine for every 79 residents and the state's 97 casinos held 45,289 machines at the end of 2006, representing 5.5 percent of all such machines in the U.S.

Oklahoma's total machine count trails only Nevada (206,419) and California (64,510), according to the 2007 version of the North American Gaming Almanac.

A local casino association leader said the increase reflects years of hard work spent building the industry.

“It used to be that 30 to 40 percent (of Oklahoma gamblers) would play here, and the other 60 or 70 percent would save their money and go to Vegas or Kansas City or Shreveport,” said Brian Foster, chairman of the Oklahoma Indian Gaming Association.

“Now I think we're keeping 60 to 70 percent here,” he said.

The annual gaming almanac, which is sold to vendors, casinos and others in the industry, also reported Oklahoma's gambling industry took in an average of $617.87 per capita, although that figure includes losses by out-of-state residents. That figure, which includes the state lottery, is nearly three times higher than in 2003.

By comparison, Oklahomans' personal per-capita income increased by 22.6 percent between 2003 and 2006, according to the state Commerce Department.

Oklahoma registered $2.2 billion in total gambling revenue in 2006, a figure that includes money spent on the state lottery.

Not everyone considers the report good news for Oklahoma.

Michael Smith, executive director of the Oklahoma Association for Problem and Compulsive Gambling, said he has seen a marked increase in the number of people with “significant” gambling problems since the 2004 ballot items took effect.

“I surely don't think anyone needs to believe that the numbers of problem gamblers are going to decrease in Oklahoma. I believe we will see the number of people statewide presenting for care increase,” Smith said.

He said the number of Gamblers Anonymous meetings in Oklahoma rose last year, as did the number of counselors who have undergone specialized training to treat the problem.

Legislators in 2004 set aside a total of $750,000 per year from the state's share of lottery and casino proceeds to treat compulsive gambling.