Year	% of population
1998	38
1999	36.7
2000	33.1
2001	27.8
2002	25.7
2003	23.5
2004	19.7
2005	19.2
2006	18.1
2007	16.6
2008	15.2
2009	15
2010	14.3
2011	13.6
2012	11.9
2013	10.6
2014	11.5
2015	10.9
2016	10.1
2017	9.8
2018	9.2
2019	9.1
2020	8.1