WASHINGTON — Growth at service companies slowed in September from an eight-year high in August as sales fell sharply, new orders declined, and hiring weakened.
The Institute of Supply Management said its service-sector index fell to 54.4 in September, down from 58.6. August’s reading was the highest since December 2005.
Any reading above 50 indicates expansion.
Service industries cover 90 percent of the workforce, including retail, construction, health care, and financial services.
The ‘‘index still points to moderate growth in the fourth quarter,’’ said Paul Ashworth, an economist at Capital Economics.
Ashworth forecasts growth in the October-December quarter at an annual rate of 2 to 2.5 percent. That would be slightly better than the 1.5 to 2 percent rate economists predict for the July-September quarter.
Ashworth said the fourth-quarter growth rate assumes the US government shutdown lasts no more than two weeks.
If it persists, the shutdown could shave about 0.15 percentage points from the fourth-quarter figure for each week it lasts, according to estimates from a number of economists.