49. As shown in table 4, whenever persons of unknown nationality acquire Dutch nationality this usually happens through naturalization (and the concomitant co-naturalization of dependants). Naturalization is normally possible after one has had legal residence in the Netherlands for five years. Stateless persons who are registered as such have facilitated access to naturalization: only three years of legal stay are required, although they must also meet a number of other integration requirements, including assimilation into Dutch society, reasonable knowledge of the Dutch language, and a certain knowledge of the Dutch political system and society.65 Nonetheless, this difference does not appear to be of much consequence: every year about 8 per cent of people from either category acquire Dutch nationality. 50. The remainder of this chapter attempts to provide an insight into the composition of the groups of registered stateless persons and persons of unknown nationality. By disaggregating and analysing these categories, we may be able to grasp the actual meaning of otherwise hollow numbers. 3.3.1 Statistics on stateless persons 51. Eurostat’s most recent 2009 survey shows the Netherlands as having a stateless population of 2,060 persons.66 Figure 1 displays the development of the number of registered stateless persons present in the Netherlands.67 Fig. 1 - Registered stateless people in NL 9000 8000 7000 6000 5000 4000 3000 2000 1000 0 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Source: CBS, situation 1 January 65 22 Dutch Nationality Act (Rijkswet op het Nederlanderschap), Articles 6(1)b and 8. 66 Eurostat 2009, available at http://tinyurl.com/mlzgzt [accessed 3 October 2011]. 67 CBS, available at http://tinyurl.com/2vsx9px [accessed 5 January 2011]. Mapping statelessness