The euro soared to its highest level in more than two years against the dollar on Friday after European Central Bank President Mario Draghi did not express concern about a strong euro zone currency, as some analysts had expected.

Some analysts had suggested that Draghi could use the Jackson Hole, Wyoming central bankers’ conference to talk the euro down. When he did not do so, traders took that as a green light to buy euros.

The dollar index dropped to a more than one-year low following Draghi’s speech and after Federal Reserve Chair Janet Yellen made no reference to U.S. monetary policy in her speech.

Europe’s single currency has climbed 13 percent so far this year against the dollar, as it benefited from political dysfunction in Washington and the Federal Reserve’s gradual monetary tightening pace. A strong euro is a headwind for the export-driven euro zone economy.

Instead of the surging euro, Draghi, in his speech at the Jackson Hole, Wyoming central banker’s conference, instead focused on other aspects such as a solid global recovery.