JANNA HERRONNEW YORK (AP) â¿¿ Fixed mortgage rates rose slightly this week, but the average rate on the 30-year loan remained below 5 percent. Freddie Mac says the average rate on the 30-year fixed mortgage rose to 4.86 percent from 4.81 percent the previous week. It hit a 40-year low of 4.17 percent in November. The average rate on the 15-year fixed mortgage increased to 4.09 percent from 4.04 percent. It reached 3.57 percent in November, the lowest level on records dating back to 1991. Mortgage rates tend to track the yield on the 10-year Treasury note, which rose this week. Investors sold off Treasurys on fears the Federal Reserve might end its bond-buying program sooner than expected. Low rates have done little to jumpstart the weak housing market. Home sales remain sluggish and prices are falling in most major markets. Most analysts expect prices to decline through midyear. More Americans did sign contracts to buy homes last month, the National Association of Realtors said Monday. But there was "a measurable level of contract cancellations" in February, meaning many pending sales might not translate into closed sales. In another dismal sign, Lennar Corp. said Tuesday that new orders dropped 12 percent from December through February, while home deliveries slipped 3 percent. High unemployment and strict lending requirements have kept many people from buying homes. And a record number of foreclosures are forcing down home prices, leaving many would-be buyers worried that the market has yet to bottom out. To calculate average mortgage rates, Freddie Mac collects rates from lenders across the country on Monday through Wednesday of each week. Rates often fluctuate significantly, even within a single day. The average rate on a five-year adjustable-rate mortgage rose to 3.70 percent from 3.62 percent. The five-year hit 3.25 percent last month, the lowest rate on records dating back to January 2005.