Existing-home sales rose 7% on a monthly basis in September, reaching a seasonally-adjusted, annual rate of 6.29 million, the National Association of Realtors said Thursday. Compared to a year ago, though, sales were down roughly 2%. The increase in sales was the result of improved inventory in recent months, which gave buyers more options to choose from and allowed more people to lock in purchases. However, inventory dropped nearly 1% from the previous month as of the end of September, and was down 13% from a year ago.