WASHINGTON (MarketWatch) -- Following various reports of weaker housing data, the 30-year fixed-rate mortgage average fell to 3.99% in the week ending March 29 from 4.08% in the prior week, Freddie Mac said Thursday in its weekly report. The rate was 4.86% a year earlier. To obtain the latest rate, payment of an average 0.7 point was required, according to Freddie, a buyer of residential mortgages. A point is 1% of the mortgage amount, charged in prepaid interest. The 15-year fixed-rate mortgage fell to 3.23% in the latest week from 3.30% in the prior week. Meanwhile, the average rate on the 5-year Treasury-indexed hybrid adjustable-rate mortgage decreased to 2.90% from 2.96%. The 1-year Treasury-indexed ARM fell to 2.78% from 2.84%.