A flash estimate of U.S. business activity in the manufacturing sector showed weak growth on a seasonally adjusted basis in May, Markit Research said. The research firm\'s purchasing managers\' index, based on 85 percent of the month\'s survey results, showed the headline index falling from 56 in April to 53.9 on a seasonally adjusted basis, the lowest level since February. The production index showed growth, but at the slowest rate in six months, Markit said. The job creation index showed slower growth for second consecutive month. By the numbers, the new orders index fell from 56.9 to 54.8, with the new export index rising slightly from 50.3 to 50.7. The employment index dropped from 56.3 to 54.3. The index uses 50 as the break-even point. Numbers above 50 indicate growth, while numbers below 50 indicate contraction. Putting the month\'s figures into perspective, Markit Chief Economist Chris Williamson said, \"U.S. manufacturing seems to be repeating the trend seen in the previous two years, whereby a strong start to the year loses momentum as summer approaches. \"This year, the cause seems to lie largely with weak export sales, which likely reflects the deteriorating economic situation in Europe as well as slower growth in China.\" That said, \"Irrespective of the slowdown in May, the U.S. manufacturing sector remains a bright spot in an otherwise lackluster global picture, and it is encouraging to see producers continuing to add to their payroll numbers in the expectation that demand will continue to rise in coming months,\" he added.