Growth in the U.S. manufacturing sector slowed more than expected in May, according to a survey of industry executives released today.

The Institute for Supply Management’s manufacturing index stood at 51.4 in May, down from a reading of 53.3 the previous month and below analysts’ expectations for a reading of 52.

The index is at its lowest level since June 2003 when it registered 50.4.

Any reading above 50 indicates growth in the sector, and the April number represented the 24th straight month of such growth.

“While this represents the longest period of growth in the last 16 years, the data also indicates that the sector is losing momentum,” said Norbert Ore, chair of the ISM’s Manufacturing Business Survey Committee, in a release.

“The rate of growth in new orders continues to decline. The manufacturing sector is definitely slowing.”

The survey’s employment subindex fell to 48.8, ending 18 straight months of hiring growth in the sector.

As well, the rate of growth in new orders in May continued to decline with only 11 of 20 industries reporting improvement compared with April.

Meanwhile, the U.S. Commerce Department said construction spending rose 0.5% to a record level in April, as office construction surged and activity in the housing market hit an all-time high.

The Commerce Department said the increase pushed building activity to a seasonally adjusted annual rate of US$1.066 trillion in April, following gains of 0.6% in March and 1.2% in February.