The Australian census is administered once every five years by the Australian Bureau of Statistics. The most recent census was conducted on 9 August 2011; the next will be conducted in 2016. Prior to the introduction of regular censuses in 1961, they had also been run in 1901, 1911, 1921, 1933, 1947, and 1954. Participating in the census is compulsory. The census counts all people who spend census night within Australia and its external and internal territories other than Norfolk Island, with the exception of foreign diplomats and their families. A separate census of Norfolk Island has been conducted by the Norfolk Island Government every five years since 1981, and occurs on the same day as the Australian census.