The Super Bowl in Glendale, Arizona, on Sunday will look like the many Super Bowls that have come before. But one thing will be different.

Some people at the game at State Farm Stadium will walk into an on-site sportsbook, make a bet, then head out to their seats to see if they win. Others won’t even bother leaving their seats; they will bet on the game they’re watching from the phones in their hands.

It is the first time legal betting on the Super Bowl is available at the Super Bowl, one more example of the explosion of legal sports betting in the past five years.

It wasn’t long ago that if you wanted to bet on sports in the United States, you had to fly to Las Vegas or hunt down a shadowy bookie. But the door is now legally open for fans to make a wager on the big game in 33 states, among them Arizona.

The total amount bet on the Super Bowl every year is unknowable. When you hand a twenty to your neighborhood bookmaker or challenge your buddy with “Five bucks says Mahomes passes here,” no one records the transaction.

But indisputably, legal betting on the big game is increasing as more and more states allow sports betting.

In 2018, the Supreme Court struck down a 1992 law that prohibited sports betting in most places outside Nevada. Over the next few years, states rushed to get into a business they saw as lucrative. The latest additions are Arkansas, Kansas, Maryland, Massachusetts and New York in 2022, and Ohio on Jan. 1 of this year. Several other states are on the brink. Some of the 33 states in which sports betting is legal allow betting online, some allow betting at a casino, and many allow both.

One state not yet on board is Missouri, home to the Kansas City Chiefs. That means fans who want to wager on their local team in the Super Bowl – or against it – will have to leave the state to do it legally.

That doesn’t sit well with many sports-betting advocates there. “They’re going to go watch the game at some sports bar in Kansas – Buffalo Wild Wings, whatever it might be, and inject money into those local economies when they could be doing it here in our state,” Republican state Rep. Kurtis Gregory told The Kansas City Star.

With more and more states allowing sports wagering and with the Super Bowl as the biggest betting attraction of the year, it is clear that legal wagering on the game is rising. Precise numbers are hard to find because not every state breaks down wagering on a game-by-game basis.

One place that does regularly record its Super Bowl betting intake is the traditional Nevada sportsbooks. They took in a record $179 million in wagers on last year’s game, the Nevada State Gaming Control Board reported. The figure broke $100 million for the first time in 2014.

A survey by the American Gaming Association, the casino industry trade group, estimates that of those who will bet on the game this year, 38% will bet online, something that was illegal almost everywhere in the country a few years ago. About 34% will bet with friends, and 26% in a pool of some kind. About 18% will bet at a legal sportsbook, whose numbers have ballooned along with the rise in legalized sports betting.

And the old-time bookie is not dead yet; 13% will bet with one, the trade group estimates.

Legal betting online and at casinos hit $950 million last year, the group estimates, up from $159 million in 2018, with the bulk of that increase caused by the rapid spread of outlets to wager.

Throw in all those friendly bets and office pools, not to mention betting with illegal bookmakers and offshore casinos, and the trade group says $16 billion will be bet by 50 million total Americans, although those numbers are impossible to verify.

And which team are most people betting on this year? Bookmakers worldwide made Kansas City the early favorite over Philadelphia, by about 1 point, right after the matchup was set. But money from so-called sharp bettors, who tend to be knowledgeable and bet early, flooded in on the Eagles. In a matter of hours, Philadelphia was favored by 2 to 2.5 points.

As the public started betting over the past two weeks, they found Kansas City more tempting at that price. While the Eagles remain favorites, the line is down to 1 or 1.5.

Others are betting on the typically wide array of bets available on the Super Bowl, including the total number of points scored, the first player to score a touchdown, and the result of the coin toss.

And many will be making their bets just between checking the weather and taking a selfie.