Twenty months ago, in November 2014, the BMW i3 electric car had only been on sale in the U.S. for six months.

But the numbers sold just in the first half-year had, surprisingly, catapulted BMW to the highest percentage of plug-in vehicles sold—2.3 percent—for any carmaker in the U.S. that isn't named Tesla Motors.

It marked, we suggested, a sign of BMW's commitment to electrifying its vehicle range, as well as the appeal of the unusual and technically sophisticated i3 five-door hatchback.

DON'T MISS: Which Electric-Car Makers Are Serious? U.S. Sales Show Top Three (Nov 2014)

Halfway through 2016, the story remains the same. BMW is still the plug-in percentage winner among the car companies selling in the U.S.

Sales of the BMW i3 have cooled off, though the 2017 i3 will go on sale later this year with about 50 percent more electric range, due to a battery capacity half again as large as the 22 kilowatt-hours of the 2014-2016 versions.

The range correspondingly rises from 81 miles for the battery-electric version to as much as 114 miles, though the lower-range version will remain in the lineup.

2017 BMW i3

2017 BMW i3

The 2,880 i3s and 620 i8s sold from January to June were joined by a whopping 2,577 plug-in hybrid X5 utility vehicles, as well as 137 new 330e plug-in hybrid sport sedans.

Together, the four models represent 3.5 percent of BMW's total six-month U.S. sales of 178,580 (including the Mini brand, but not Rolls-Royce).

The plug-in hybrid models delivered recently have been somewhat rolled under the "i" sub-brand, by the way, as they're now dubbed "iPerformance" variants.

CHECK OUT: Electric Cars: Some Are Real, Most Are Only 'Compliance Cars'--We Name Names (May 2012)

A new second-place arrival, meanwhile, has only been selling plug-in cars of any type in the U.S. for 11 months.

That would be Volvo, whose 1,006 XC90 T8 'Twin Engine' plug-in hybrid luxury SUVs made up 2.8 percent of its total six-month U.S. sales of 36,520.

Both numbers exceed Nissan's half-year percentage (its 5,793 Leafs are just 0.7 percent of 798,114 six-month U.S. sales) and GM's (9,808 Volts and 1,779 Spark EVs make up 0.8 percent of its 1.44 million total sales).

2016 Volvo XC90 T8 'Twin Engine' plug-in hybrid, Spain, Feb 2015

2016 Volvo XC90 T8 'Twin Engine' plug-in hybrid, Spain, Feb 2015

As CleanTechnica noted in May, electric cars now make up 2.5 percent of BMW sales globally.

Finally, one last contender might seem to be the Smart brand, which has sold as many as three or four of every 10 ForTwo cars in the U.S. with the Electric Drive option.

But Smart has to be rolled into the far higher totals for Mercedes-Benz, which has sold only 310 of its B-Class Electric Drive this year on top of the electric Smarts, plus fewer than 100 plug-in hybrids—putting it far down the list as well.

_______________________________________

Follow GreenCarReports on Facebook and Twitter.