Just when it seems like the bottom's dropped out, the average rate of 30-year fixed-rate mortgages has slipped again. According to Freddie Mac's Primary Mortgage Market Survey, 30-year fixed-rate mortgages averaged a rate of 4.42 percent, down from 4.44 percent last week. It marks the ninth straight week in which the rate has met or set a new record low, said Freddie Mac's Deputy Chief Economist, Amy Crews Cutts. At this point last year, the average was 5.12 percent. Fifteen-year fixed-rate mortgages also hit a milestone, bottoming out at a record-low 3.90 percent, down from last week when it averaged 3.92 percent. Just one year ago, the average rate was 4.56 percent. Cutts cites the end of the homebuyer tax-credit as a continued impediment to home sales. Will we see a drop in 30-year fixed-rate mortgages for a 10th week in a row? It may be more surprising if we don't.