Not surprisingly, newly released figures indicate the Toyota Prius is the best-selling automobile in the tech-savvy Silicon Valley.

Although nationwide the Prius is outsold by Toyota's own Camry and Corolla models and Honda's Civic and Accord, between January and May the Prius accounted for five percent of the new vehicles registered in Santa Clara County, California.

The study, conducted by R.L. Polk, an automotive industry research firm, found that 30,463 cars and trucks were registered in the county during the five-month period.

Rod Diridon, executive director of the Mineta Transportation Institute at San Jose State University said, in an interview for the Associated Press, that the popularity of the Prius could be attributed to multiple factors.

Among those he cited were global warming and the continued high level of national gasoline prices. Diridon, himself, drives a Prius.

According to statistics compiled by the U.S. Environmental Protection Agency, the 2007 Prius remains the most fuel-efficient vehicle on America's roads today.

Average fuel economy for the Prius is 60 miles per gallon for in-town driving and 51 mpg on the road. Overall, Prius sales across the nation were up 96 percent over the same time period for last year.

Even given these encouraging numbers, however, sales of the Toyota Prius, which total 94,000 units to date, account for roughly one percent of all car and truck sales in the United States.

In recent months criticism has arisen over long-term maintenance issues with the Prius and pundits have suggested that cleaner burning diesel fuel may gain greater popularity with the buying public than hybrid technology.