The battle between the Nissan Leaf and Chevy Volt continues. June 2011 auto sales figures were posted today and the Nissan Leaf has taken a commanding lead. Last month, 1,708 Nissan Leafs were sold, up from 1,142 Leafs sold in May 2011 and significantly higher than the 573 sold in April. Year-to-date Nissan Leaf sales total 3,875.

General Motors also saw an increase in sales of their newest electrified vehicle, the Chevy Volt, during June. In May 2011, Volt sales totaled 481 units. That number jumped up to 561 for June, bringing year-to-date Volt sales to 2,745. At the end of May 2011 there was only a 17-vehicle margin between year-to-date Leaf and Volt sales but now that has jumped to 1,130.

In other fuel-efficient vehicle news, Toyota is still plagued by slowed production due to the March earthquake and subsequent tsunami that wreaked havoc on parts of Japan. Sales of the Toyota Prius, dropped to 4,340 in June 2011. This is a 62.1 percent decline from the same month last year when nearly 11,000 Priuses were sold. Despite the production woes, Prius sales for the year top 66,000, which allows the Prius to continue its reign as the best-selling hybrid.

Lexus, Toyota’s luxury line of automakers, sold a total of 840 hybrids during the month. The newest hybrid in the Lexus lineup, the CT 200h, posted sales of 240 units bringing year-to-date CT sales to 3,768. The sporty compact hybrid has only been available for four months.

Honda hybrid sales have also slowed. In June 2011 American Honda Motor Co. only sold 1,021 insights (34.2 percent decline from last year), 966 CR-Zs and 418 Civic Hybrids (36.5 percent decline from 2010).

In 2008 when gas prices reached record highs and then normalized, sales of hybrids and fuel-efficient vehicles spiked and then fell off. As gas prices begin to return to a more reasonable level this summer, auto sales may begin to show the same trend.