31 million American adults plan to place a traditional sports wager online, at a retail sportsbook or with a bookie.

21.5 million plan to bet casually with friends.

56.3 million plan to participate in a bracket contest.

“March Madness is one of the best traditions in American sports—and America’s most wagered-on competition,” said AGA President and CEO Bill Miller. “Critically, the expansion of regulated sports betting over the past five years has brought safeguards to more than half of American adults who can now bet legally in their home market.”

The growth in March Madness betting is driven by a resurgence of bracket contests as well as Americans taking advantage of the expansion of legal online wagering. Three-fourths of online bettors say this will be their first time betting on March Madness online.

While 18 million more American adults plan to wager on March Madness compared to last month’s Super Bowl, Americans are expected to wager half a billion dollars less on the tournament than they planned to wager on the Big Game.

Since last year’s tournament, Kansas, Massachusetts and Ohio have launched retail and mobile sports betting markets, while Maryland has launched mobile wagering. This year’s March Madness—with 67 games over three weeks—will be the first to feature Las Vegas as a regional host location.

“With the excitement around March Madness, the AGA and our members want to remind anyone getting in on the action to have a game plan to bet responsibly. That means setting a budget, knowing the odds, keeping it social and always playing legally,” added Miller.

Among bettors, Kentucky is the most popular choice to win the national title (9%), followed by Texas A&M (8%), and Gonzaga, UCLA and Alabama (6%).