The construction sector posted another strong month as overall payroll gains continue the trend of the last four years. The U.S. economy added 200,000 private non-farm jobs in March, according to a monthly employment report released today by payroll-processing company ADP and its partner Moody’s Analytics. Of those gains, 43 percent came from business with fewer than 50 employees. The seasonally adjusted monthly figure is on par with February’s downward-revised 205,000 payroll additions, matching job-growth trends over the past four years and reflecting a tightening in the labor market with steady increases across regions and sectors, said Moody’s chief economist Mark Zandi in a conference call this morning.