NEW YORK (CNN/Money) - U.S. manufacturing activity expanded at a brisk pace last month, exceeding Wall Street forecasts, the nation's purchasing managers said Tuesday.

The Institute for Supply Management (ISM) said its index of manufacturing activity rose to 62.8 in May from a revised 62.4 the prior month. Economists, on average, expected an ISM index of 61.5, according to Briefing.com.

In January the index stood at a two-decade high of 63.6.

The yearlong stretch of strong growth also helped power the ISM's employment index to 61.9 in May -- the highest since April 1973 -- from 57.8 the prior month. But after shedding nearly 3 million jobs for more than three years, the factory sector has a long way to go to recover all the jobs lost.

The ISM index is compiled from monthly responses by purchasing executives at more than 400 industrial companies, ranging from textiles and chemicals to paper and computers.  

-- from staff and wire reports