Toyota continues to invest so heavily in hybrids because the company's Prius was the first hybrid to truly to go mainstream.

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 study conducted earlier this year by research firm R.L. Polk showed that almost two-thirds of hybrid buyers didn't purchase another one. Yet Toyota, one of the world's largest automakers, continues to crank out hybrid versions of most of its models.

Perhaps this is because the company's iconic Prius was the one exception in the study above--58 percent of Prius buyers bought another hybrid, according to Toyota (Polk's number was slightly higher at 60 percent). Data from analyst firm AutoPacific shows the number at only 31.8 percent, but that's still better than the Honda Accord (26.1 percent) and the Toyota Camry (30.1 percent).

2012 Toyota Prius 2012 Toyota Prius

We reached out to Toyota to gain some insight into the company's strategy. Other brands aren't necessarily backing off of hybrids, but Toyota is by far the most committed, with 20 new hybrids planned globally by 2015.

Looking at the numbers Toyota provided, it's not hard to see why. The company has sold 4.4 million hybrids worldwide to date, and the Prius alone has 50 percent of the hybrid market for 2012. Toyota is attempting to capitalize on the it's reputation in a big way.

When asked why Toyota remains so committed to hybrids even in the face of the numbers from the Polk study, Erica Gartsbeyn, marketing product manager, responded: "We are seeing our buyers coming back so it’s easy for us to be committed to hybrid technology. This technology is helping customers reduce their environmental footprint while fulfilling their vehicle needs."

There are reasons why hybrid buyers might not return, though, and Toyota acknowledges that.

"Customers might not return to a hybrid due to the price premium or if their specific product needs are not available with preferred brand or body style," Gartsbeyn said.

Toyota continues to invest so heavily in hybrids because the company's Prius was the first hybrid to truly to go mainstream, and Prius owners are fiercely loyal. From a marketing perspective, it makes sense for the company to try and encourage Prius owners who need more space to step into a hybrid Camry.

It's not that other automakers' hybrids are inferior (indeed, there is a bit of an MPG arms race among hybrids right now), but rather that Toyota has cultivated a reputation for selling hybrids that its rivals haven't.