Those who won in 2013 didn't contribute to the $23.8 billion raked in by Indian casinos that year.

According to a report released Monday, March 30, by Orange County–based economist Alan Meister, Indian gaming was a $23.8 billion business in 2013, the most recent year for which comprehensive figures are available.

Nearly a quarter of that revenue was generated in California, making the state the national leader in tribal gambling income.

Still, overall revenues were up just half a percent compared to 2012, the slowest gain since the Great Recession. While one new casino opened near the end of the year in Northern California, currently the only new project in the works is the hotly contested Hollywood Casino being developed in Jamul.

Having reached what appears to be near-peak demand, tribes are turning to other forms of non-gambling entertainment. Several casinos have opened or expanded resort-style hotels and amenities in northern and eastern San Diego in recent years, with non-casino operations bringing in nearly $800 million per year statewide.

"That’s a major theme throughout Indian gaming," Meister said in a release ahead of the report. "The casinos need to reach out to access new customer segments in order to compete. In every state, the vast majority of the expansion projects are in non-gaming."