During the NFL’s regular season, the teams with the best odds heading into each game won more often than ever, a windfall for bettors.

As the Kansas City Chiefs travel to New Orleans to seek their third consecutive Super Bowl title, a win would crown an apropos champion to an NFL season dominated by favorites.

Unlike college football this year where an 8-seed Ohio State knocked off a 7-seed Notre Dame in the National Championship game, the NFL has been a bit different.

The 2024 National Football League regular season was the most favorite-friendly or “chalked,” season in the history of the league. As it relates to sports betting, chalked refers to a contest going the way bookmakers expected.

This year, the favorite won 196 times, the most in an NFL season, according to Sports Odds History. The previous record was in 2005, when the favorite won 188 times.

That was helped by the regular season expanding to a 17-game schedule in 2021. But the winning percentage of the odd-on favorite also spiked to 72.1% in 2024. That’s up from the 66.2% average from 2020 to 2023 and the highest since 2005.

That’s bad news for sportsbooks, online betting operators, and state gaming commissions, which clean up primarily through underdog victories. By contrast, individual gamblers typically go with the safe bets, and their pockets grow when favorites prevail.

“The 2024 NFL Regular Season, especially in the final weeks of the year, were very favorable to bettors, seeing many favorites win on a weekly basis,” Fanatics Sportsbook NFL Trader Ethan Useloff told Fortune in a statement.

In fact, Nevada sportsbooks lost more than $2 million on football in December, the first time a net loss on football has occurred since November 2012, ESPN reported.

The public loves betting on chalk. The most bet-on team this season on Fanatics’ Sportsbook platform was the Detroit Lions, who boasted a 15-2 record that was tied for the NFL’s best with the Kansas City Chiefs.

Bettors have taken advantage of the chalked NFL schedule. In a week 14 matchup when the heavily favored Philadelphia Eagles squared off against the struggling Carolina Panthers, a gambler in Kentucky placed a $3.1 million bet on the Eagles. At -700 odds, the bettor won $442,857.

A bettor turned to Reddit to voice their frustrations about favorites’ consistent track record. “In all the years I’ve been gambling, I’ve never seen so many favorites winning across multiple weeks like this. What’s going on?” the post said.

Chalk didn’t cover the entire football season. In September, the NFL recorded 26 upsets, netting Nevada sportsbooks $80.9 million, the most profitable month of all time in the state’s history, ESPN reported.

But for the remainder of the season, underdogs won only 29.7% of their games.

Fanatics told Fortune that single-team wagers weren’t the sole reason for bettor success this year. An increasingly popular bet known as a parlay was also a factor in bettor prowess. A parlay allows users to make one bet on multiple events happening, offering low odds but big rewards.

“Lots of Fanatics Sportsbook customers cashed in parlays, turning a small wager into a sizable win,” Useloff said.

Favorites’ unprecedented success affected more than just sportsbooks and Las Vegas; it affected state governments that legalized online sports betting to generate more tax revenue.

During the NFL regular season, the sport was at the top spot in Vermont’s monthly wagering reports. But on Jan. 16, the state cut its adjusted gross wagering revenue projection by nearly $800,000. Originally, for the fiscal year, its first since sports betting became legal in January 2024, the state predicted that it would bring in roughly $7 million in gaming revenue.

Liquor and Lottery Commissioner Wendy Knight said bettors are winning more, forcing the state to cut its budget. But Vermont will still see other benefits from bettors’ winnings.

“They’re going to pay income tax on what they’ve won, they’re going to go out to dinner more, they’re going to take a vacation, they’re going to buy a new rug,” she told lawmakers at a hearing. “The winning payouts would circulate into the economy.”

By contrast, bettors in New York, where legal online market began in January 2022, are getting killed by the books—and filling up government coffers.

In October, New York earned $2.32 billion in gross gaming revenue off mobile sports wagering, according to the state’s Gaming Commision, topping the previous high of $2.1 billion in November 2023.

From September to December, the Empire State has earned $8.9 billion in revenue from sports betting, up from $7.9 billion during the same four-month period a year ago.

With the Super Bowl a week away, sports bettors are preparing for their biggest event of the year. Last season, the game saw $23.1 billion wagered across the country, a 285% increase from 2019, the first year after the Supreme Court struck down a ban on sports betting.

While the regular season was heavily chalked, the playoffs have been more mixed. The favorites won only 50% of the time in wild card and divisional round games, then swept the conference championship round.

For the Super Bowl, the Chiefs are a very slight favorite over the Eagles at –130 to take the title.