Businesses added 166,000 jobs in September, payroll processor ADP said Wednesday, as employment continued a recent trend of more modest gains.

Economists expected ADP to report 180,000 additional jobs, according to a consensus forecast.

ADP revised its previously reported August figure from 176,000 to 159,000.

Small businesses added 74,000 jobs; large companies, 64,000; and midsize ones, 28,000.

Trade, transportation and utilities led job gains, with 54,000. Professional and business services added 27,000. And construction companies added 16,000. But manufacturers added only 1,000 and financial firms cut 4,000.

"Fiscal austerity has begun to take a toll on job creation," says Mark Zandi, chief economist of Moody's Analytics, which helps ADP conduct the survey. "The run-up in interest rates may also be doing some damage to jobs in the financial services industry."

Economists expected the Labor Department to report about 180,000 job gains in its survey, which tallies net job increases among businesses and all levels of governments. That report, which was scheduled to be released Friday, could be delayed because of the government shutdown.

The job market has slumped recently amid federal spending cuts and a January payroll tax increase. Monthly job growth has averaged about 148,000 the past three months, vs. 224,000 the previous three months, according to the Labor Department.

ADP has had mixed success in forecasting Labor's report. Last month, it estimated that businesses added 176,000 jobs in August, while Labor reported just 152,000 new private-sector jobs. ADP says it strives to closely track the government's final revised numbers.