Updated

Federal Reserve Chair Janet Yellen says the economy has come a long way in recovering from the 2008 financial crisis, and the Fed is getting close to achieving its goals of maximum employment and stable inflation.

But in a speech in San Francisco, she says she can't say when the next interest rate will occur or how high rates will rise. She says that will depend on how the economy performs in the coming months.

She says Fed officials, who boosted rates for a second time last month, expect to raise rates "a few times a year" until they have pushed the Fed's benchmark rate close to 3 percent by the end of 2018. The rate now stands in a range of 0.5 percent to 0.75 percent.