U.S. service industries, representing about 80 percent of the nation's economy, grew faster than expected in October, with increasing numbers of orders, according to a survey of purchasing and supply executives.

The Institute of Supply Management's index for services was 55.8 in October, rising from 54.8 in September. Figures above 50 show expansion. Analysts had expected the index to read 54 in October.

Non-manufacturing business activity increased for the 55th consecutive month in October, said ISM Chair Anthony Nieves.

The overall indication in October is continued economic growth in the non-manufacturing sector at a faster pace than in September.

The report showed nine industries rising in October. The biggest gainers were mining, retail trade, construction and real estate.

The four industries showing slower activity from September to October were, Management of Companies & Support Services; Information; Wholesale Trade; and Public Administration.