Mortgage rates have fallen to their lowest level in decades, according to mortgage buyer Freddie Mac.

The average rate for a 30-year fixed loan is 4.32 percent, which is down from 4.36 percent last week.

The low rates mean a high number of borrowers are in the process of refinancing. In fact, they make up over 80 percent of all new loans.

Despite the low rates, the housing market remains weak. The number of people buying previously-owned homes is still well below where it was a year ago.