I like to keep an eye on electric car sales. It's not the most fascinating thing in the world, but it's a kind of barometer for the green transportation sector.* So to recap a bit, not all plug-in manufacturers break out their sales per month - for example, Tesla only gives updates for each 3-month period, with Oct-Dec showing sales of 6,900 Model S EVs - while others like GM and Nissan give sales info for each month.
The full-year 2013 figures for those were 22,610 for the Nissan LEAF, more than doubling its sales from 2012 (9,819) and pushing it over 100,000 cumulative EVs sold, and 23,094 for the Chevrolet Volt.
*But as we always say, the greenest way to get around is to walk, bike, or take transit. But that's not always possible for everyone (those of us who live in dense cities full of great transit infrastructure and bike lanes sometimes forget that half of world population lives outside of cities, and many of those who do live in cities are stuck in car-centric suburbia). That's why plug-in vehicles are so important.