U.S. retail sales unexpectedly fell in December as unseasonably warm weather undercut sales of winter apparel and cheaper gasoline weighed on receipts at service stations, adding to signs that economic growth braked sharply in the fourth quarter.

The Commerce Department said on Friday retail sales slipped 0.1% after an upwardly revised 0.4% gain in November.

Economists polled by Reuters had forecast retail sales unchanged after a previously reported 0.2% rise in November. For all of 2015, retail sales rose 2.1%, the weakest reading since 2009, after rising 3.9% in 2014.

Retail sales excluding automobiles, gasoline, building materials and food services fell 0.3% after a downwardly revised 0.5% rise the prior month. These so-called core retail sales correspond most closely with the consumer spending component of gross domestic product.

Core retail sales previously were reported to have advanced 0.6% in November. Economists had forecast them rising 0.3% last month.

The mixed retail sales report joins weak data on construction, manufacturing and export growth in suggesting that economic activity cooled significantly in the final three months of last year.

It could raise concerns that the manufacturing and export-oriented sector malaise was filtering to other parts of the economy. Manufacturing has been bruised by a strong dollar and sluggish global demand. Business efforts to cut an inventory overhang and energy sector spending cuts have also been a drag.

The core retail sales drop last month and the downward revision to the November figure could prompt economists to lower their fourth-quarter GDP estimates, which currently range between a 0.5% and a 1.4% annual rate. The economy grew at a 2% pace in the third quarter.

Auto sales were unchanged after rising the prior month. Receipts at service stations fell 1.1% after decreasing 1.3% in November.

Sales at clothing stores dropped 0.9% as unusually warm weather hurt sales of winter apparel. Sales at online retailers edged up 0.3% and receipts at sporting goods and hobby stores rose 0.9%.

Sales at electronics and appliance outlets fell 0.2%. Receipts at building materials and garden equipment stores rose 0.7% likely boosted by warm temperatures. Furniture store sales gained 0.9%.