OSLO, March 9 (Reuters) - Growth in the Norwegian business sector has declined slightly over the past three months while the outlook for the next half year is more optimistic, a central bank business survey showed on Tuesday. “Contacts expect activity to pick up again, and they are more optimistic than in November, primarily owing to the roll-out of vaccines,” Norges Bank said. The sentiment index, most of which was collected from Jan. 25-Feb. 12, is one of the last domestic data releases ahead of Norges Bank’s March 18 monetary policy meeting. (Reporting by Terje Solsvik, editing by Gwladys Fouche)