It is only where such activity is carried on for less than a year that it should not be separated from the activities of the producer institutional unit. This may also be done where the activity, though conducted for a year or more, is insignificant, and in all circumstances for the installation of equipment abroad. But a unit which is resident in another country and which is carrying out a construction activity in the country for a duration of less than a year is deemed to have a centre of economic interest on the economic territory of the country if the output of the construction activity constitutes gross fixed capital formation. Such a unit should therefore be treated as a notional resident unit.