WASHINGTON — U.S. home sales fell for the sixth straight month in September, a sign that housing has increasingly become a weak spot for the economy.

The National Association of Realtors said Friday that sales declined 3.4 percent last month, the biggest drop in 2 ½ years, to a seasonally adjusted annual rate of 5.15 million. That’s the lowest sales pace since November 2015.

Hurricane Florence dragged sales down in North Carolina, but even excluding the storm’s effects, sales would have fallen more than 2 percent, the NAR said. After reaching the highest level in a decade last year, sales of existing homes have declined steadily in 2018 amid rapid price increases, higher mortgage rates and a tight supply of available houses.

Still, analysts are mostly optimistic about the broader economy. Most forecast growth will top 3 percent at an annual rate in the July-September quarter, after a robust expansion of 4.2 percent in the second quarter.

“Housing is no longer a tail wind for the economy, but the headwinds are blowing very gently,” said Michelle Meyer, an economist at Bank of America Merrill Lynch, before the report was released.

Housing will likely weaken further in the coming months. September’s weakness came before mortgage rates jumped further this month to their highest levels in seven years. Sales fell 4.1 percent in September from a year ago.

“Without a doubt there is a clear shift in the market,” said Lawrence Yun, chief economist at the National Association of Realtors.

One sign of the shift is that demand for existing homes is slowing. Home prices are rising at a slower rate and the supply of available houses, while low, is increasing. Buyer traffic has also declined, Yun said.

And with rents also stabilizing in many cities, many would-be buyers may not feel as much pressure to buy a new home.