With U.S. sales of plug-in electric cars now averaging more than 10,000 vehicles each month, September sales achieved that mark but fell short of the sizzling pace of the last two months.

Sales of the Nissan Leaf totaled 2,881 last month, bringing year-to-date deliveries to 21,882.

That's almost a 50-percent increase over last September's sales of 1,953, and it marks the Leaf's 19th consecutive month of year-over-year increases.

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The Leaf is by far the world's best-selling plug-in car. Just under 64,000 Leafs have been sold in the U.S. since the battery-electric hatchback went on sale in December 2010.

Volt lowest since Feb

The Chevrolet Volt, on the other hand, logged deliveries of just 1,394--its lowest volume since February--and lower than the previous September's 1,766. The total sales through September are 14,540.

That brings the range-extended electric car's total sales to 69,092 since it went on sale the same month as the Leaf.

With a new 2016 Chevy Volt to be introduced in January at the Detroit Auto Show, sales of current 2014 and 2015 Volt models seem likely to remain low for the next several months.

Along with the Tesla Model S--whose monthly sales are not reported--the Leaf and Volt make up the bulk of U.S. electric-car sales each month.

The BMW i3 electric minicar--the one with the optional two-cylinder range-extending engine--sold 1,022 last month, the second month in a row it has exceeded 1,000 units.

That's an impressive performance for a new contender, and it brings the five-month total for the i3 to 3,104.

Plug-in hybrids purr along

Sales of plug-in hybrid vehicles from Ford and Toyota make up the next largest segment of the plug-in market.

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The Toyota Prius Plug-In Hybrid is actually the third highest-selling car with a plug in the U.S. since it went on sale in 2012--through last month, the total was 11,842.

But September sales were an astoundingly low 353 vehicles, the lowest since February 2012--the first month the car went on sale.

Sales for Ford's pair of Energi plug-in hybrid models, the C-Max compact hatchback and Fusion mid-size sedans, were lower than in previous months as well.

The plug-in C-Max sold only 677, its lowest monthly figure since April, and plug-in Fusion sales plummeted to 640 from more than three times that number in June.

Year-to-date totals for the pair of Energi cars are 6,486 and 9,323 respectively--meaning that Ford overall continues to sell more plug-in hybrids this year than Toyota.

Low-volume vehicles and compliance cars

Bringing up the third category are almost a dozen different cars with plugs that sell in low volumes or count as compliance cars, those sold solely to meet California rules mandating sales of certain numbers of zero-emission vehicles.

The first to report was GM, with 111 Cadillac ELR range-extended luxury coupes sold last month, bringing the year's total to 885.

The low-volume group includes the BMW i8 plug-in hybrid sports coupe--of which 58 were sold in its second month on the market (adding to the 9 sold in August).

2014 Ford Fusion Energi

The plug-in Panamera, however, continued strong, with 82 sales--bringing its year-to-date totals to 694, representing 14 percent of all U.S. sales for Porsche's largest four-door luxury sedan.

The Honda Accord Plug-In Hybrid sold 42 cars, meaning its year-to-date total was 309. On sale since January 2013, just 835 have been delivered over that period.

In its third month on the market, the Mercedes-Benz B-Class Electric Drive delivered 65 cars, for a total thus far of 159.

The Mitsubishi i-MiEV electric minicar delivered another 15 units, bringing its year-to-date sales to an anemic 149 units.

The Ford Focus Electric saw 176 sales last month, roughly on pace with the average so far this year, which has totaled 1,534 electric Focuses over nine months.

And the tiny Smart Electric Drive delivered 182 units, its lowest since February, but also about on pace with its year-to-date average. The total for 2014 thus far is 1,780 electric Smart cars.

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Among the compliance cars, meanwhile, first to report was Honda, which delivered 27 FIt EVs. That brings the nine-month total to 347 and the overall total since 2012 to 1,009--approaching its cap of 1,100 units.

Similarly, the Toyota RAV4 EV, with sales of 125 in September and a year-to-date total of 967, has now sold 2,255 altogether--approaching its announced volume of 2,600 units.

In other words, both vehicles are likely approaching the end of their tenure in the market.

The Chevrolet Spark EV, too, was off its prior pace, with just 51 sold--the lowest number since the 27 delivered in May 2013, its very first month on sale.

Fiat refuses to break out sales of the electric 500 from other models, so we don't have figures for the last of the four compliance cars.

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