WASHINGTON — Rates on 30-year mortgages, which shot up last week to the highest level in nearly a year, dropped slightly this week following passage of a housing rescue bill.

Freddie Mac reported yesterday that the nationwide average for 30-year mortgages dipped to 6.52 percent this week, down from 6.63 percent last week.

Rates on other types of mortgages also fell this week, according to the Freddie Mac survey.

Rates on 15-year fixed-rate mortgages, a popular option for refinancing, fell to 6.07 percent, down from 6.18 percent last week.

Rates on five-year adjustable-rate mortgages also dropped to 6.07 percent, down from 6.16 percent last week. Rates on one-year adjustable-rate mortgages declined to 5.27 percent, compared to 5.49 percent last week.

A year ago, rates on 30-year mortgages stood at 6.68 percent, 15-year mortgage rates averaged 6.32 percent and one-year adjustable-rate mortgages averaged 5.59 percent.