U.S. companies added the fewest jobs in four months in October, as construction and manufacturing firms continued to shed workers, a private survey says.

Payroll provider ADP says businesses added 147,000 jobs, down from 202,000 in September, a figure that was revised strongly higher.

October's hiring, while below last year's healthy pace, is enough to lower the unemployment rate over time. The economy has shown signs of picking up in the second half of the year after a weak start.

The ADP data cover only private businesses and often diverge from the official figures. Economists forecast that the government's jobs report, to be released Friday, will show a gain of 170,000 jobs, according to data provider FactSet. The unemployment rate is expected to decline to 4.9 percent, from 5 percent.