WASHINGTON, July 6 (Xinhua) -- The U.S. service sector grew in June for the sixth consecutive month, but at a slower rate than in May and short of economists' expectation, an industry trade group reported Tuesday.

The Non-Manufacturing Index (NMI), which measures activities in the service sector, dropped to 53.8 last month from 55.4 in May, the Institute for Supply Management (ISM) said in its monthly survey.

A reading above 50 indicates the service sector is generally expanding, while below 50 indicates contraction. Economists had expected a reading of 55.0 for June.

The index is closely watched because the service sector absorbs about 80 percent of U.S. non-farm workforce, and is a key indicator for the overall health of the economy and labor market.

Meanwhile, the New Orders Index decreased 2.7 percentage points to 54.4 in June, and the Employment Index slipped 0.7 percentage point to 49.7, according to the report.

Fifteen industries reported growth in June, including real estate, entertainment, information and others, while finance and insurance is among the few industries that reported contraction.