Trade group says U.S. service sector grew in May

A trade group says the U.S. economy's service sector grew in May for an 18th straight month, posting slightly faster growth than in April.

The Institute for Supply Management says its index tracking the health of service companies, which employ 90 percent of the nation's work force, increased to 54.6 in May compared to 52.8 in April.

The past three months have had lower readings than in February, when the index hit a five-year high of 59.7. Any reading over 50 indicates expansion.