In May, the Toyota Prius Prime plug-in hybrid was the highest-selling car with a plug in the U.S. for only the second time ever.

Last month, however, the Chevrolet Volt recaptured its usual spot at the top of the plug-in sales charts for those manufacturers who report monthly sales.

Chevy sold 1,745 Volts, slightly down from the May number of 1,845, but still enough to push the six-month total into five figures, at 10,932.

DON'T MISS: Plug-in electric car sales for May: best Bolt EV, Prime months yet; Leaf, Volt rise too

Added to that were deliveries of 1,642 Bolt EV 238-mile battery-electric hatchbacks, the latest in a string of best monthly totals and enough to take the Bolt's six-month aggregate to 7,592 deliveries all told.

Next month will finally see the Bolt EV rolled out to all 50 states, at which point its sales potential may become clearer.

Still, General Motors sold 3,394 plug-in cars (including a surprise 7 units of the discontinued Cadillac ELR plug-in hybrid sport coupe).

2016 Cadillac ELR

2016 Cadillac ELR

We don't know how that compares to the number of Teslas sold last month, because the Silicon Valley electric-car maker refuses to report monthly sales broken down by country.

It is rumored to have highly irregular month-to-month delivery totals, with a massive push to get totals up in the third month of each quarter.

Tesla did report that its second-quarter deliveries for May through June were slightly over 22,000 cars globally, though what proportion of those represent U.S. sales remains unclear.

READ THIS: Tesla's Q2 2017 deliveries fall slightly due to 100-kwh battery shortage

The Prius Prime, meanwhile, logged sales of 1,619, bringing its half-year total to 9,692, giving it the second-highest sales total thus far in 2017 after the Volt.

The Nissan Leaf, meanwhile, logged 1,505 sales—its best performance so far in 2017—for a year-to-date total of 7,246 deliveries. The redesigned, longer-range 2018 Nissan Leaf will be unveiled on September 6.

Note that the Leaf total is now somewhat below that of the Bolt EV, however, which has been on the market all of six and a half months, and not country-wide at that.

2017 BMW i3

2017 BMW i3

Other higher-volume plug-in electric models had a mix of good and not-so-good months.

The BMW i3 logged 567 deliveries to reach a six-month total of 2,992 units so far. The June sales figure was essentially on pace with its performance this year.

The Volkswagen e-Golf, meanwhile, lagged at just 232 delivered for 2017 sales of 1,992 so far—a slower pace than usual and one that could indicate trouble in clearing out remaining stocks of 2016 models before the longer-range 2017 e-Golf arrives at dealers.

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Audi sold 324 A3 e-tron plug-in hybrid hatchbacks, slightly down from its stronger pace of about 400 per month earlier this year. That car's six-month total is now 2,120 units.

Porsche, meanwhile, continues to sell substantial volumes of its Cayenne S E-Hybrid plug-in hybrid luxury SUVs: it delivered 195 last month, giving it a year-to-date six-month total of 978, a respectable number even given the Cayenne's importance in the Porsche lineup.

No data is available yet for sales of the Volvo XC90 T8 plug-in hybrid SUV, while sales numbers for Ford's pair of plug-in hybrid Energi models and its Focus Electric compliance car will be reported later today.

We'll update this article as more data arrives.

EDITOR'S NOTE: As of May, this monthly report covers only plug-in electric cars with sales of 100 units a month or more—with occasional exceptions for new models, exceptionally large changes in sales volume, or other newsworthy events.


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