U.S. mortgage rates fell in step with bond yields in the wake of weaker-than-expected domestic economic data and as investors scaled back expectations about the number of interest rate increases by the Federal Reserve in 2017, according to Freddie Mac on Thursday.

The borrowing cost on 30-year mortgages, the most widely held type of U.S. home loan, averaged 4.02% in the week ended May 18, down from 4.05% the previous week, the mortgage finance agency said.