I have no hard data, but I suspect a significant portion of hybrid owners are concerned about green technology and used that in their decision process.

Just talking to prospective buyers on this site you'll find most of them haven't decided on the model and just debating hybrid versus conventional engine. No, they're usually considering an array of vehicle options. Being able to tick off 'Green' goes into the plus column.

Think of it as the American way. Why sacrifice to save the environment when I can buy something to do it for me.