Wholesale companies added more autos, machinery and computers to their stockpiles in June, pushing inventories up for the 18th consecutive month.

Sales at the wholesale level rose 0.6 percent in June, the Commerce department said Wednesday. That followed a 0.3 percent drop in May. Sales have risen in 10 of the past 12 months.

Stockpiles increased 0.6 percent in June after a 1.7 percent gain in May.

Wholesale stockpiles have risen to $458.7 billion, up 19.6 percent from the low point hit in September 2009.

Rising sales could give businesses confidence to keep restocking their shelves. That could boost growth at a critical time when many fear the chances of another recession have increased.

For June, stockpiles of autos rose 4.3 percent, computers gained 3.5 percent and machinery increased 1.8 percent.

The ratio of inventories to sales was unchanged in June at 1.16. That means it would take 1.16 months to exhaust the current level of stockpiles.

Steven Wood, chief economist at Insight Economics, said the ratio was very close to the record low of 1.13 hit in March. Leaner stockpiles and rising sales typically suggest wholesalers will boost factory orders in the months ahead, he said.

The economy expanded at an annual rate of just 0.8 percent in the first six months of the year, the slowest growth since the recession officially ended two years ago. In June, consumers cut spending for the first time in 20 months and saved more. Wages are barely growing.

Hiring has slowed from the start of the year. Employers added 117,000 net jobs in July, an improvement from the previous two months. Still, more than twice that number are needed to significantly drive down the unemployment rate, which was 9.1 percent last month.

U.S. manufacturing has been one of the strongest sectors of the economy since the recession ended. Efforts by businesses to restock depleted shelves have fueled much of that factory production.

But factory activity weakened in the spring, in part because of supply chain disruptions caused by the Japan crisis. As a result, U.S. manufacturers have had a difficult time getting component parts, particularly for autos and electronics.

The Federal Reserve on Tuesday said it expects the economy will stay weak for the next two years. As a result, it said it planned to keep interest rates at super-low levels for at least through mid-2013.

The Fed hopes that by providing more certainty to businesses and consumers, it will be able to spur increased borrowing and economic activity.