Along with General Motors reporting the company’s highest overall sales month since September 2008, the Chevrolet Volt’s sales crested higher to 1,607 units sold in May compared to 1,306 units sold in April.

May’s results do however lag 4.3-percent behind the Volt’s May 2012 score of 1,680 units sold, and follow Nissan’s all-electric Leaf’s May sales of 2,138 cars delivered.

The Leaf and Volt are only comparable in some ways, given the Volt is an “extended-range” EV, not a pure electric car, but both were launched the same month in 2010, and it has become tradition at this stage to keep tally.

Nissan’s sales were boosted in part by U.S. production, a 14-percent increase in battery range on a full charge, and an otherwise fairly comprehensive mid-cycle refresh.

General Motors has not announced price cuts for the Volt, and the 2014 model is expected to be released this summer, which may have some potential customers holding back.

Meanwhile, GM said its sales overall are especially buoyant and the Cadillac brand in particular was up 38 percent, its largest increase since 1976.

The aggregate picture saw GM Co. May 2013 sales of 252,894 vehicles delivered in the United States. This represents a 3-percent rise compared to one year ago. Retail sales were up 9 percent, fleet sales were down 10 percent and the fleet mix was 26 percent of total sales.

As for the Volt – which may have benefited from the rising tide – various deals around the country are on offer for the 2013 Volt and have assisted with gains made. In some cases, incentives have seen some people netting the car for well below $30,000 on a net-adjusted basis.

The Volt also must overcome persistent critics who have linked the car to political issues.

Reviewers ordinarily like or even love the Volt however and it has racked up as many or more awards and acknowledgments than any car in recent memory.

It is over-engineered, GM does sell it at a loss, and it’s the only plug-in hybrid with enough all-electric range to make 35-45 miles driven an easily attainable task.

A second generation of the car is believed pending on a new platform for 2015 or maybe 2016 based on previous statements made by key company executives, but GM has not officially confirmed second generation details, preferring instead to focus on the unit it now has to sell.