Sales of plug-in electric cars continued at a steady pace in April, with 493 Chevrolet Volts and 573 Nissan Leafs sold during the month.
That brings yearly totals of the cars to 1,703 and 1,025 respectively.
There were also 326 Volts and 19 Leafs sold last December, the month in which each car first went on sale.
Each month since then, Chevy has sold more Volts than Nissan has Leafs. This is the first month in which Leaf sales, at 573, slightly exceeded Volt sales, at 493.
Chevrolet had warned that its April total would be lower than last month's 608, as Chevy diverted cars that might otherwise have been sold to paying customers to provide more dealers with Volt demonstration vehicles.
That trend may continue for a while, given Nissan's challenges in resuming full-scale production of its various models in Japan. All Leafs sold in the U.S. will be built in its plant in Oppama, Japan, until early 2013.
Chevy has said it will sell roughly 10,000 Volts during 2011, and Nissan recently confirmed that it expects to sell a similar number of Leafs in the United States this year.
With a total of 2,029 Volts sold, that model now becomes the highest-selling highway-capable electric car in the U.S. It surpassed estimated total deliveries of 1,650 for the Tesla Roadster since it went on sale very late in 2008.
First 2011 Chevrolet Volt delivered to retail buyer Jeffrey Kaffee, in Denville, NJ, December 2010
Tesla Motors has consistently declined to report on its monthly sales. Each quarter's sales of its $109,000 Roadster and Roadster Sport models only become apparent once it files required information with the Securities and Exchange Commission.
Small Indiana electric-car maker Think had not returned our calls for monthly sales by the time Chevrolet and Nissan reported.
Among other electric cars in the market, Smart also declined to report its monthly sales of the 2011 Smart Electric Drive, after delivering the first one in January.
"We are not yet prepared to report a separate break out for the electric drive," said Smart's Rick Bourgeoise, "We only have 250 cars in total this year, and [we] can start to report in July when all of the vehicles have arrived."
As of April, Fisker Automotive had not begun retail deliveries of its 2011 Karma luxury sports sedan, a plug-in hybrid.