The percentage of manufacturing and distribution companies in Maryland who say they are doing well is about half of the national mark, according to a new survey. In the 2014 Manufacturing & Distribution Monitor by McGladrey, a CPA and consulting firm, 36 percent of such companies nationwide call themselves thriving, as opposed to 17 percent among the 31 respondents in Maryland. The group described as declining represented 7 percent in Maryland, about the same as the national 5 percent. The percentage of firms holding steady in Maryland was higher than nationally — 76 percent to 60 percent. In last year’s survey, 24 percent in Maryland said they were thriving. Half of the state companies in the survey planned to add to their workforce. Nationwide, that figure was 57 percent.