CHICAGO (Reuters) – The Federal Reserve has not done enough to lower U.S. borrowing costs to boost economic growth, a top Fed official said on Friday, citing his outlook for overly low inflation and overly high unemployment over the next two to three years.

Since the Great Recession, workers and businesses are seeking safer assets, even as the supply of assets perceived as safe dwindles, Minneapolis Fed President Narayana Kocherlakota told a group convened by the University of Chicago Booth School of Business.