Sales of existing homes slipped in September.

The National Assn. of Realtors said sales of existing single-family homes dropped a slight 1.7% in September following a big 11.5% August increase. The brisk pace of sales in August and September, the highest since a 3.48-million-unit pace in November, 1979, was credited to falling interest rates. “This clearly underscores the positive impact lower interest rates are having on housing markets nationwide,” said David D. Roberts, president of the association and a realtor from Mobile, Ala. The median price of an existing home fell $1,600 in September to $75,300, a 2% decline that followed a 0.6% August decrease.