Friday evening, when perhaps not a lot of people were watching, a virtual odometer ticked over on the Chevy Volt website.

At that hour--about 7 pm Eastern--it showed that Volt drivers had covered 100,000,000 miles on electricity in their range-extended electric cars.

(The actual total is about 25 percent higher, since the counter only logs miles from those 80 percent of owners who've agreed to let Chevy track their performance via the Onstar telematics system.)

That's out of the roughly 160,000,000 miles those tracked Volts have traveled in total.

Which reflects the fact that Volt owners cover almost two-thirds of their total distance on electricity--higher than General Motors had expected, we imagine, when it launched the Volt in December 2010.

In fact, GM will soon release an app that lets Volt drivers compete on electric miles driven.

And the Volt electric-mile counter continues to rise. When this article was published--just two and a half days later--the total had already risen 1.2 percent.

Other electric-miles totals include 29 million-plus miles in the global fleet of about 2,500 Tesla Roadsters.

As for the new Tesla Model S, owners of the thousand or more electric luxury sedans delivered so far (Tesla won't say how many) have logged 1.9 million miles to date, according to Tesla spokeswoman Christina Ra.

Then, courtesy of BMW electric-car advocate Tom Moloughney, we can add a total of 10 million miles (globally) in that company's fleet of 700 Mini E test cars. 

The company's current electric-car test program, using the BMW ActiveE two-door sedan, is closing in on 4 million miles of its own.

And so forth.

A little more than a year ago, we reported that electric cars had covered about 35 million miles on electricity in the U.S. alone.

Given the sales of Volts, Nissan Leafs, Toyota Prius Plug-In Hybrids, and at least nine other plug-in cars today, total electric mileage could be approaching 10 times that figure.

And that's just the start.

When will we reach 1 billion electric miles driven in the U.S.? Ten billion?

Leave us your thoughts in the Comments below.

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