U.S. private-sector employers added 158,000 jobs in March, the smallest gain in five months and short of economist expectations, according to a report Wednesday by payrolls processor ADP. The private sector had added 237,000 net jobs in February and 177,000 in January. The March decline was attributed to the construction sector. Construction companies did not add any jobs in March, after average monthly gains of 29,000 the previous three months. The ADP survey comes ahead of the government's more comprehensive labor-market report on Friday, which includes both public and private hiring and is expected to show a gain in overall non-agriculture jobs of 200,000 last month, with the unemployment rate holding steady at 7.7 percent. The ADP report suggests that the government jobs figures may be below economist predictions. But other reports suggest that the job market is improving. The number of people making initial jobless claims is lower now than in February, meaning companies are cutting fewer jobs, and a closely watched survey of manufacturing activity showed factories hired in March at the fastest pace in nine months.