We missed a milestone a couple of weeks ago: Toyota built and sold its two-millionth Prius hybrid earlier this month.

The first-generation Prius, the world's first production hybrid-electric vehicle, was launched in Japan late in 1997. It stayed a low-volume car for several years, and wasn't brought to the States until a revised version was produced for the 2000 model year.

Indeed, sales stayed below 100,000 a year until the launch of the radically styled second-generation Prius in 2004. It took more than 10 years to rack up sales of the first million Priuses, but just two and a half years for the second million.

More than 400,000 Prius models were sold in 2009 across more than 70 different countries or regions.

Of the total of 2 million, U.S. and Canadian buyers took almost 940,000 Prius models. Following that is Japan, where 825,000 have been sold--and where the Prius was the best-selling car last year due to strong tax incentives for the purchase of cars with the highest fuel efficiency.

The success of the Prius led Toyota to pledge that it would offer a hybrid variant of every mass model it sells by 2015. After the Prius, the most popular hybrid Toyota is the Camry Hybrid, with roughly 200,000 sold globally. Altogether, Toyota has sold 2.8 million hybrids ... and counting.

Toyota calculates that the 2 million Prius sales alone have reduced global emissions of the greenhouse gas carbon dioxide (CO2) by about 11 million tons, compared to conventional gasoline cars of the same size and performance.

The 2011 Toyota Prius gets a combined EPA mileage rating of 50 miles per gallon, continuing its reign as the most fuel efficient car sold in the U.S. Prices start at $23,050.