A lucky customer of the Kwick Pick Market in Rohnert Park bought a winning Lotto ticket for a $13 million jackpot, the California Lottery announced on its website Saturday.

Just who picked the right six numbers, the only ticket in California to capture the top prize in the Superlotto Plus game, was a mystery to Kwik Pik employees Saturday night.

"I want to know who won, you know?" said Ramon Gutierrez, 35 of Santa Rosa, who was manning the store. "I see a lot of customers, and I don't know. I've worked here for 13 years, and it's nice to hear somebody won."

Gutierrez said he played, but he didn't win. Even so, he was buoyed by the news.

"Somebody was lucky, that's good," he said with a laugh.

It was the biggest lottery win in Sonoma County in four years.

In February 2008, Elba Escamilla of Petaluma, who had never before played the California lottery, claimed an $80 million jackpot.

The winning numbers Saturday were 2, 3, 10, 22, 25 and the meganumber of 7.

The state lottery posted the store location where the winning ticket was sold about 8:30 p.m. and officials were not available for comment on whether the winner had stepped forward.

Since 1990, at least 14 residents of Lake and Sonoma counties have won $1 million or more in the state lottery, not counting Saturday's winner. A Middletown couple won $50 million in 2002, and in 1992 a Cloverdale couple won $19 million. Petaluma residents have won in 1990 for $15.5 million and another time in 1994 for $4.5 million.

Winners can choose to take their windfall in a lump sum or installment payments. There is no state tax on lottery winnings, but under the lump sum option, federal income tax will be withheld at the rate of 25 percent for U.S. citizens. Winners get 45 to 55 percent of the jackpot -- the cost of a 26-year annuity -- when they take a lump sum.

Under the annual payment option, winners are responsible for paying their own federal taxes each year. Each year they get a larger check, starting with 2.5 percent of the jackpot.