This year marks the 10-year anniversary of the Toyota Prius, which continues to be America’s best-selling hybrid vehicle year after year. Although several new hybrid vehicles have come to the market in the past 12 months, including the reasonably priced Honda Insight and the highly acclaimed Ford Fusion Hybrid, neither of these vehicles has been able to dethrone the Prius.

Although the Prius continues its reign as the king of all hybrids, sales are still down in 2010. In July 2010, Toyota sold 14,102 Prius models. While this was up from the 10,998 sold the month prior, it is down 29.2 percent from the more than 19,000 models sold in July 2009. Overall, Toyota’s total sales were down 6.8 percent when compared to the same time period last year.

Despite Toyota’s overall decline in sales, a few models saw a big jump in numbers including the 20-mpg Toyota 4Runner (+248.1 percent), the 19-mpg Toyota FJ Cruiser (+231.0 percent), the 16-mpg Toyota Sequoia (+50.5 percent), and the 17-mpg Toyota Tundra (40.3 percent).

While gas prices aren’t anywhere near the highs of summer 2008, gas prices are higher this summer than they were last summer. According to the American Petroleum Institute (PDF), regular gasoline is up about 5.1 percent compared to the same time period last year.

Unfortunately this year-over-year increase in gas prices was not high enough to push the demand for hybrids, as we saw during the summer of 2008. However, the relatively stable gas prices are good news for Toyota as is evidenced by the huge jump in sales for gas guzzling, pricier full size SUVs and trucks.