WASHINGTON — Rates on 30-year mortgages edged down slightly this week, but remained above 6 percent for the third straight week.

Mortgage giant Freddie Mac reported yesterday that 30-year fixed-rate mortgages averaged 6.05 percent this week, compared to 6.06 percent last week. It marked the third week that 30-year rates have been above 6 percent.

Analysts said no mortgage rates changed much this week as the housing industry continues to confront the worst downturn in more than 20 years.

The Freddie Mac survey found that rates on other types of mortgages were mixed this week.

The average rate on 15-year fixed-rate mortgages, a popular choice for refinancing, edged up to 5.60 percent, from 5.59 percent last week.

Five-year adjustable-rate mortgages dropped to 5.67 percent, down from 5.73 percent last week. One-year adjustable-rate mortgages were unchanged for a third straight week, remaining at 5.29 percent.