LAS VEGAS — Sports books in Nevada took in $81.5 million in bets on Sunday's Super Bowl and won $6.68 million, state gambling regulators said Tuesday.

The amount bet on the game was below $90 million for the first time since 2004, when sports books took in $81.2 million in wagers. But the 8.2 percent the state's 176 sports books won was an improvement over last year when they lost a record $2.6 million on the big game, according to numbers released by the state Gaming Control Board.

Jay Kornegay, executive director of the race and sports book at the Las Vegas Hilton, said he was surprised by the low betting volume and had expected about $90 million in wagers.

"That's a huge drop," Kornegay said. "Going into the weekend ... we were a little concerned. By midmorning Sunday, we were pleasantly surprised by the volume that we saw coming through the windows."

The Pittsburgh Steelers beat the Arizona Cardinals in Tampa, Fla., but Arizona bettors who bet on the 6›- to 7-point spread won when the game ended 27-23.

Kornegay said the sports books were able to control betting they received on either side by manipulating the point spread a half-point in either direction.

Last year, Nevada casinos took in $92 million when the New York Giants upset the New England Patriots, 17-14, and handed the state's sports books a loss on the Super Bowl for the first time since 1995, when the San Francisco 49ers trounced the San Diego Chargers 49-26.

The record amount bet in Nevada sports books on the Super Bowl was $94.5 million in 2006 when the Steelers beat the Seattle Seahawks, 21-10. Casinos won $8.8 million that year.