WASHINGTON (AP) — Manufacturing grew at a faster pace in September than in August, though the pace of growth remains weak.

The Institute for Supply Management, a trade group of purchasing executives, says its manufacturing index increased to 51.6, up from 50.6 in August. A reading above 50 indicates expansion. The increase follows two months of declines.

Measures of production and exports grew, while a gauge of new orders was unchanged. Factories also added workers, the report says.

The manufacturing sector has been a key driver of the economy's growth since the recession officially ended in June 2009. The index topped 60 for four straight months earlier this year. It rose above 50 a month after the recession ended and has topped that level ever since.