March 2015 plug-in sales in the U.S.

A total of 10,291 plug-in vehicles were sold in the U.S. in March. The list is still headed by the Tesla Model S (2,400), followed by the Nissan Leaf (1,817) and Fiat 500e (1,310). That means almost 85 percent of all Fiat 500e sold in the U.S. in 2015, were sold last month. Also, the Nissan Leaf now officially overtakes the Chevrolet Volt in terms of total sales, since both cars hit the market at the end of 2010.
ev-sales.blogspot.co.uk (figures), transportevolved.com (Leaf/Volt)