Year	% of population
1996	17.5
1999	23.4
2000	19.1
2001	18.4
2002	18.2
2003	17.4
2004	16.7
2005	16
2006	17.8
2007	16.6
2008	15.4
2009	14.2
2010	13.3
2011	12.5
2012	12
2013	11.4
2014	11.3
2015	11.2
2016	10.9
2017	10.6
2018	9.8
2019	9.4
2020	9.8
2021	10.1
2022	9.5
2023	9.4