U.S. factories slowed their pace of expansion in output last month, but factories added more workers, a survey released Monday said.

The Institute for Supply Management (search) said its manufacturing index slipped to 62.4 in April from March's 62.5. Economists had forecast a rise to 63.0.

A reading above 50 shows expansion. It was the 11th consecutive month of expansion in the sector that makes up less than a fifth of the U.S. economy. In January, the index stood at a two-decade high at 63.6.

ISM said the employment component of the index rose to 57.8 from 57.0 in March.

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