Golden Gate Bridge, connecting San Francisco and Marin County, California
Different vehicles appeal to different markets. More than half of all Chevrolet Suburban extra-long full-size sport utility vehicles, for instance, are sold in the state of Texas.
So where do plug-in electric cars tend to cluster?
Not surprisingly, in progressive regions with activist governments that provide incentives for their adoption, whether purchase rebates and carpool-lane access or widespread public charging networks.
The latest data comes from R.L. Polk, which analyzed national sales of all vehicles with plugs.
Those include both battery-electric vehicles like the Nissan Leaf and Tesla Model S, and the wide variety of vehicles with both plug-in battery packs and engines, including the Chevrolet Volt and many different plug-in hybrids from Ford, Honda, and Toyota.
The data tracked by Polk showed that more than half of all plug-in electric vehicles are now registered in just five metropolitan regions.
They are, in order: San Francisco, Los Angeles, Seattle, New York, and Atlanta.
By comparison, roughly one-third of the nation's hybrids are registered in the same cities.
It's not surprising that California has the number-one and -two slots; the state has been at the forefront of reducing vehicle emissions for half a century.
And starting in 2012, it enacted rules that required the six top-selling automakers to sell a certain number of zero-emission vehicles each year.
Almost two years ago, when fewer electric cars were found on U.S. roads, sales data on hybrids and plug-in electric cars combined showed that their penetration was greatest in the San Francisco Bay Area.
But beyond San Francisco, are these the locations where you would have expected to find plug-in electric vehicles?
Leave us your thoughts in the Comments below.