WASHINGTON, Dec 16 (Reuters) – U.S. business inventories increased slightly more than expected in September, suggesting inventories probably added to economic ​growth in the third quarter.

Inventories rose 0.2% after being unchanged ‌in August, the Commerce Department’s Census Bureau said. Inventories are a key component of ‌gross domestic product and one of the most volatile. Economists polled by Reuters had forecast inventories rising 0.1%. They increased 1.2% year-on-year in September.

The report was delayed by the recently ended 43-day shutdown of the ⁠government.

Retail inventories increased 0.4% in ‌September after being unchanged in August. Motor vehicle inventories jumped 1.2% after gaining 0.1% in August. Retail inventories ‍excluding autos, which go into the calculation of GDP, were flat for a second straight month.

Wholesale inventories rose 0.5% in September while stocks at manufacturers ​fell 0.1%.

Business inventories decreased at a $18.3 billion annualized rate in the ‌second quarter, subtracting 3.44 percentage points from GDP. That was, however, more than offset by a record 4.83 percentage point contribution from a smaller trade deficit.

The Atlanta Federal Reserve is forecasting gross domestic product increased at a 3.6% annualized rate in the third quarter. The government ⁠will release its first estimate of third-quarter ​GDP on December 23 after it was ​delayed by the shutdown. The economy grew at a 3.8% pace in the April-June quarter. While the rebound in ‍inventories likely added ⁠to GDP growth last quarter, it also reflected softening demand.

Business sales were unchanged in September for the second consecutive month. Sales ⁠at retailers ticked up 0.1%. At September’s sales pace, it would take 1.37 ‌months for businesses to clear shelves, unchanged from August.

(Reporting by ‌Lucia Mutikani; Editing by Chizu Nomiyama)