The World Cup is here, and the betting spree on the outcome of individual games and the final has begun.

About 20.5 million American adults plan to bet a total of $1.8 billion on the 2022 FIFA World Cup in Qatar, according to a survey by the American Gaming Association, a gambling industry trade group.

Of those, 48% intend to place their bets online and 29% said they plan to bet casually with friends. Meanwhile, 23% plan to bet at a physical casino sportsbook and 20% plan to place a bet with a bookie.

Just over three-quarters of respondents said it’s important for them to place their bets legally. And this year, betting on the World Cup will be easier than ever after the Supreme Court ruled in 2018 to end a federal ban on commercial sports betting, opening the door to many states legalizing it.

“As the first World Cup with widespread availability of legal sports betting, this will certainly be the most bet-upon soccer event ever in the U.S.,” AGA senior vice president, Casey Clark, said in a statement. “With more than half of all American adults having access to legal betting options in their home market, legal sports betting will deepen American fan engagement in the most-watched sporting event in the world.”

Washington D.C. and 31 states —home to 132 million Americans—currently have legal sports betting markets, with five additional legal markets awaiting launch, according to the AGA. That compares with only 10 million people in three states who could legally bet on the 2018 World Cup.

The survey found that Gen Zers and millennials are more likely to bet on the soccer tournament than Gen X and baby boomers. Eleven percent of Gen Z adults and 14% of millennials said they were interested in betting on the World Cup compared to only 8% of Gen X and 2% of baby boomers.

So who exactly are people betting on? When asked who they’d put their money on if given $50, 24% said they’d wager on the United States winning—reflecting their home country bias. Another 19% said they’d bet on Brazil, 17% said Argentina, and 10% said Germany.

Whatever the case, bettors are advised to be prudent.

“As the World Cup kicks off, anyone getting in on the action should have a game plan to bet responsibly,” Clark said. “That means setting a budget, keeping it fun, learning the odds and playing with legal, regulated operators.”