The EV Project, an organization funded by the DoE, has released data from 8,000-plus plug-in vehicle owners.  The data dates back to 2009 and shows that most EV owners are 45 to 54 years of age with a household income of more than $200,000.

There's loads of additional data gleaned from these 8,000-plus drivers, which is all rolled into the hand infographic seen below: