The continuity of residence required to acquire the right of permanent residence is not affected by temporary absences not exceeding six months per year, nor by absences of a longer duration for the fulfilment of military obligations or by an absence of up to twelve consecutive months for an important reason, such as pregnancy, childbirth, serious illness, study, vocational training or secondment abroad for professional reasons. The continuity of residence required to acquire and maintain the right to permanent residence may be attested by any means of proof.