Mortgage buyer Freddie Mac said Thursday that the average on the 30-year loan dropped to 3.66% from 3.71% last week. It's the lowest rate since long-term mortgages began in the 1950s.

The average rate on the 15-year mortgage, a popular refinancing option, declined to 2.95%. That's down from 2.98% last week and just above the record 2.94% of two weeks ago.