Toyota Prius

American consumers bought more hybrid gas-electric cars in December than any other month in 2010. Sales tallied to 28,592, which is a 13.6 percent increase in hybrid sales compared to Dec. 2009—and a whopping 37 percent increase from November sales.

The December jump in hybrid sales outpaced the overall growth in the U.S. auto market, which grew by 11.1 percent. For the year, the size of the American auto market also expanded by 11 percent—while hybrids fell by a little more than 5 percent. It’s important to note that most of the growth in the overall vehicle market came from light trucks (a category that includes pickups, vans and many SUVs). Light trucks rose by 21 percent while passenger cars grew by just 1 percent.

The hybrid market continues to be dominated by one vehicle: the Toyota Prius. In Dec. 2010, Toyota sold 15,639 Priuses, nearly a 33 percent increase from last December. This allowed Toyota to post a slight half-percent gain of U.S. annual Prius sales—coming in a year in which concerns about the safety of Toyota vehicles, specifically the “runaway” Prius, produced sensational negative headlines and production stoppages.

Perhaps most striking is that Prius sales were flat in 2010, when overall Toyota sales dropped by 5.5 percent last year. The Toyota Prius represented 8 percent of all Toyota vehicles sold in the U.S. in 2010.

In December, Prius returned to the best-seller list for passenger cars. When you exclude pick-up trucks and SUVs, the Prius was the eighth most popular vehicle in the U.S. in December. Other Toyota hybrids did not fare as well. The company sold 3.3 percent fewer hybrids in 2010. This provides a clue to why Toyota is eager to introduce an entire line of Prius vehicles, in an effort to brand much of its hybrid technology with the Prius badge.

Gas prices were on the rise in December, partly explaining the 33 percent month-over-month Prius sales increase. Unfortunately, no other hybrid model had a similar dramatic increase.

Later this week, HybridCars.com will post a full set of hybrid and diesel sales numbers—as well as the first 326 Chevy Volt and 19 Nissan LEAF purchases.