And that number is only going to grow over the next couple of years, said David Forman, vice president of research at the AGA. Americans are on track—for the first time ever—to legally bet more than $100 billion on sports by the end of the year, he said.

“Part of that is due to expansion into new markets that we didn’t have last year,” Forman said, noting that sports betting through the third quarter brought more than $7 billion in revenue for the commercial industry, up 53% from last year. “But part of it is also just a continuing maturation of existing markets that have only been online for a year or two at this point.”

The growth was primarily driven by Maryland, Massachusetts, Nebraska and Ohio, the latest states to open sports betting operations, according to a news release from the AGA.

Sports betting has always been appealing to sports and gambling fans, and has become more widely available since a Supreme Court decision in 2017 that has ultimately allowed states to decide for themselves whether or not to legalize sports betting.

“Consumers have been able to take a lot of that spending that they were doing—betting on sports with a local bookie or with an offshore website—and move that business to legal U.S. sportsbooks, where they’ll have some level of consumer protection that the offshore books don’t afford,” he said. “And be more sure that they’ll get paid out at the end of the day.”

It’s difficult for many states to not seriously consider legalizing sports wagering, because it is such a substantial source of additional revenue, said Jay Kornegay, executive vice president at the Westgate’s SuperBook, noting that the popularity of sports betting is at an “all-time high.”

Americans have always loved sports, he said, and the widespread introduction of sports betting to dozens of states has first and foremost become a new source of entertainment for them.

“Sports fans have found a new source of entertainment, and that’s sports wagering,” he said. “Now that you can make a legalized, regulated wager on a sporting event, it gives them another option of entertainment.”

As sports betting gains traction—with the AGA report showing that the industry ultimately brought in $2.15 billion in revenue in the third quarter, up almost 23% year-over-year—there’s still a long way to go before its growth plateaus, Kornegay said.

More states are predicted to embrace legalized sports betting as a source of income, especially as it proves to be beneficial to their peers, he said.

“So I would anticipate that this growth that we’re seeing right now is going to continue for the next five to 10 years at least,” he said. “And from that point, I think it’s going to be (a) consistent source of revenue for the states. I find it very unlikely that it would dip once it reaches that level.”

Sports betting has generated billions in revenue this year, but it’s important to remember that it’s just a small piece of the gaming pie, Forman said. Slots and table games, and casinos overall, are still the industry’s “bread and butter.”

Nevertheless, sports betting’s growth will be something to watch for the foreseeable future.

“There are still some really big markets out there that either haven’t legalized yet or haven’t come fully online yet—like Florida, Texas and California being the most prominent,” Forman said. “So I think we’ll still see markets that have only been online for a year or two continue to mature, and then there’s a couple of really good markets out there that are yet to legalize (and) provide more runway for growth.”