Mortgage rates have fallen in recent weeks after climbing last summer when the Federal Reserve began talking about reducing the monthly bond purchases it was making to keep long-term borrowing rates low. Mortgage rates often follow the yield on the 10-year Treasury note. Data released Thursday showed that sales of existing homes rose for the fourth straight month in July to their highest level in nearly a year, the latest sign that the housing recovery is picking up after stumbling at the start of the year. The National Association of Realtors said home sales rose 2.4 percent to a seasonally-adjusted annual rate of 5.15 million, the highest since last September.