Swiss watch exports plunged the most in at least two decades as the coronavirus pandemic led to factory closures, shuttered shops and travel bans.

Shipments plunged 81% to 328.8 million francs ($310 million) in April, according to the Federation of the Swiss Watch Industry. That’s the biggest drop in at least two decades.

Swiss watchmakers are already bracing for the worst year in the modern history of watchmaking as the coronavirus outbreak led to a virtual standstill of production and shuttered stores. Richemont Chairman Johann Rupert on May 15 warned of “grave economic consequences” that could last three years.

“Trends are unlikely to improve materially until the back half of the year,” Thomas Chauvet, an analyst at Citi, wrote in a note to clients.

Read more: Rolex, Swatch Slash Production in Watchmaking’s Worst Year

China was the best-performing market with a drop of 16%, accounting for a third of Swiss watch exports. Most other countries saw exports decline by more than 60%.

This article was provided by Bloomberg News.