The U.S. dollar index, which measures the dollar’s value against six currencies of major trading partners, is up more than 3.6 percent this year, pushing it to its highest level since April 2017. It was up 0.2 percent on Thursday.

The dollar has risen more than 1 percent against China’s government-managed currency, the renminbi, in February alone. For the year, it’s up more than 3.5 percent against the euro, 3 percent against the yen and more than 2.5 percent against the British pound.

Those regions have faced a flurry of lackluster economic results.

Official reports this month showed that the British economy flatlined during the fourth quarter. A report last week showed that the Japanese economy shriveled at a 6.3 percent annual clip during the fourth quarter, in part because of a tax increase. And this week, survey data about economic sentiment in Germany tumbled anew, as the country’s manufacturing sector copes with the fallout of the coronavirus outbreak in China, a key customer for its industrial goods and automobiles.

“Currencies are weakening on incoming bad data that leads to inflows into dollar assets,” wrote Ben Emons, global macro strategist at Medley Global Advisors.