The average rate for a 30-year fixed loan sank to 4.69 percent this week, beating the low set in December and down from 4.75 percent last week, Freddie Mac said Thursday. Rates for 15-year and five-year mortgages also hit lows.

Rates are at their lowest since the mortgage company began keeping records in 1971. The last time they were any cheaper was the 1950s, when most long-term home loans lasted just 20 or 25 years.