A U.S. interest rate hike this year would be a mistake, a top Federal Reserve official said on Thursday, and would represent a missed opportunity to boost employment and too-low inflation in an economy that has plenty of room to grow. “The (Fed policy-setting) committee needs to make policy choices that will lead to more great years like 2014,” Minneapolis Fed President Narayana Kocherlakota said in remarks prepared for delivery in Helena, Montana, citing the dramatic improvement in the U.S. labor market last year.