FRANKFURT — European car sales went over a cliff in March, falling to their lowest level in at least 30 years, according to data published Friday that provided one of the first concrete indications of the economic damage caused by coronavirus lockdowns.

Most of the previous available economic data dated from before the lockdowns began and is all but useless. Also, the car industry is a bellwether for overall economic growth in the European Union because it is a pillar of manufacturing and employs so many people — 2.6 million, or 9 percent of all factory workers in the bloc. Based on the March sales numbers, the outlook is not good.

New car registrations fell by more than half from a year earlier, to 570,000 from 1.3 million, the European Automobile Manufacturers Association said. It was by far the worst March for auto sales since at least 1990. Comparisons before then are of limited value because Europe was still divided by the Iron Curtain.