According to the National Insurance Crime Bureau, 22,441 vehicles were stolen in Clark County in 2006, a rate of 1,311 stolen for every 100,000 residents that year.

That rate was actually lower than 2005's, when thieves took 22,465 vehicles — 1,360 vehicle thefts for every 100,000 Clark County residents.

"I make no excuses for it. We're at number one, and it's a dubious distinction," Lt. Robert Duvall, who heads the Las Vegas police's auto theft unit, said Monday.

Auto thefts were down across the nation by about 2.3 percent in 2006, but they weren't down enough in Clark County to keep it from the top spot, said Frank Scafidi of the National Insurance Crime Bureau.

He said Clark County's ranking is the culmination of the year-to-year trend the organization has been tracking since 2001, he said.

"If you look back over the past few years, Las Vegas was three, then two then one," Scafidi said.

Officials have said the Las Vegas Valley is a good place for car thieves because of the population growth and high number of parking garages and parking lots.

About a quarter of the vehicles stolen in Las Vegas and unincorporated Clark County are taken by professional car thieves who often run "chop shops" that take apart vehicles and sell the parts, police officials said.

The remainder of the cases are "transportation thefts," where vehicles are stolen to get from one place to another. Those cases include not just "joy rides" but also cars stolen for use in other crimes.

The 1996 Honda Accord was the car most frequently stolen in Nevada in 2005. The 1995 Honda Civic and 1990 Toyota Camry were second and third on that list. Those older vehicles were stolen most often because there are a lot of them on the road and their parts can be sold easily, authorities said.

Duvall said Las Vegas police stepped up several anti-car theft programs in 2006, including ramping up the multi-agency Viper unit to crack down on professional auto thieves, launching multiple public awareness campaigns and using "bait cars" to catch suspects.

"We're learning, and we're catching the right people," he said.

Five of the top ten areas for auto theft were in California, according to the National Insurance Crime Bureau. Stockton, Calif., had the second highest rate of auto theft in the nation, followed by Visalia-Porterville in Central California.