Online gambling in the United States could generate $4 billion in revenue by 2020, according to findings announced Thursday from research group Technavio.

That figure includes all online betting, including online casinos and the Internet lottery. Many states have looked at or launched online lottery sales, while only a few states currently have online casino gambling.

New York, Pennsylvania, Michigan and California could all join Nevada, New Jersey and Delaware in the online casino gambling realm by 2020.

Right now, New Jersey, which had roughly $150 million in online casino gambling revenue last year, controls more than 90 percent of the American market for that activity. Nevada and Delaware both have small populations, and the former only offers online poker.

The global online gambling market is currently worth around $37 billion a year, as about 85 nations across the world have legalized some form of Internet gambling. The Technavio findings come shortly after Juniper Research found that the value of all online bets globally (not revenue) will approach $1 trillion by 2021.

According to Technavio, the US was mostly recently ranked eighth in the global online gambling market, trailing China, the UK, Australia, France, Italy, Germany and Spain.

“In the US, the average age of an individual visiting a casino is 45 years, whereas the average age of an online gambler is 34 years," Ujjwal Doshi, a lead analyst at Technavio, said. “The increasing presence of younger population on the online gambling platforms will be one of the significant factors driving the growth of the market during the forecast period.”