( b ) activity conducted for a year or more on the economic territories of several countries ; only that part of the unit which has a centre of economic interest on the economic territory of the country is deemed to be a resident unit . ###>b ) activit exerc e pendant une dur d' un an ou plus sur le territoire conomique de plusieurs pays : seule la partie d' unit qui a un centre d' int r t conomique sur le territoire conomique du pays est consid r e comme tant unit r sidente .