Sales of plug-in electric cars were essentially flat in the U.S. last year compared to 2014, and this year isn't necessarily going to be much better.

Part of that is due to product cadence: the Nissan Leaf and Tesla Model S, two of the top-selling cars in previous years, are now relatively old vehicles.

The Chevy Volt plug-in hybrid is only in its second year, and it's selling adequately, but few other high-volume models have entered the market.

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But with the Volt's sibling the Bolt EV electric car soon to start sales in some regions, it's possible a new and higher-volume vehicle will enter the market.

An executive at battery supplier LG Chem said yesterday it expected to deliver "more than 30,000" batteries for Bolt EVs in that car's first 12 months on the market.

Given that number, and the lack of a second-generation Nissan Leaf or any major ramp-up in sales of BMW i3 or Volkswagen e-Golf vehicles, which vehicle will sell best next year?

We asked that question of our Twitter followers, and indeed the Bolt EV was the winner, with almost half of respondents—46 percent—picking it as the best-selling plug-in vehicle in the U.S. for 2017.

It was followed by the Tesla Model S, which will be in its sixth model year by then, chosen by more than a third of participants, at 36 percent.

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We had expected the Toyota Prius Prime to rate higher than it did; the new plug-in hybrid version of the market's most fuel-efficient gasoline vehicle garnered only 10 percent of the votes.

And the aging and unusual-looking Nissan Leaf—still by far the world's best-selling electric car—was chosen as next year's U.S. best seller by a mere 8 percent of respondents.

2017 Chevrolet Bolt EV, road test, California coastline, Sep 2016

2017 Chevrolet Bolt EV, road test, California coastline, Sep 2016

2016 Tesla Model S

2016 Tesla Model S

2017 Toyota Prius Prime Premium

2017 Toyota Prius Prime Premium

2016 Nissan Leaf

2016 Nissan Leaf

The real numbers for next year will be tough to compare unless Tesla Motors changes its long-standing policy of refusing to break down its quarterly delivery figures by country.

While other outlets prefer to approximate Model S deliveries through registrations and other aggregated data, those numbers don't compare apples-to-apples to the sales figures issued by virtually every other carmaker.

It's hardly surprising that the Chevy Bolt EV was picked as next year's best-seller. Its EPA range rating of 238 miles was higher than expected, and reviews of the car have been largely positive.

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But for real competition, we may have to wait until 2018, when a brand-new generation of Nissan Leafs hits the market, with their own longer-range version and perhaps less polarizing lines.

There's also the Tesla Model 3, which is supposed to go into production before the end of next year as well.

Still, the omens seem to look good for the Bolt EV—always assuming Chevy dealers can educate the public about its virtues and sell the groundbreaking electric car in sufficient volumes.

You can view the results of all our recent Twitter surveys on our Polls page.

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