General Motors also suffered, largely because a strong March 2012 month for the Chevrolet Volt extended-range plug-in meant a weak month, by comparison, in 2013, as sales dropped 35 percent to 1,478 units. In fact, save for the Buick Regal eAssist mild hybrid, all GM advanced powertrain vehicle sales declined in March, with GM totaling 4,068 alt-fuel units, down 23 percent from a year earlier. Meanwhile, Honda continued its downward trend.