Year	% of population
1991	9
1992	8.7
1993	8.2
1994	10.5
1995	10.2
1996	9.2
1997	9.7
1998	9.2
1999	8.7
2000	9.5
2001	9.2
2002	9.2
2003	9.7
2004	9.7
2005	10.5
2006	10
2007	9.7
2008	10
2009	10.7
2010	10.2
2011	10
2012	11
2013	11
2014	11.7
2015	11.7
2016	12
2017	12.7
2018	11.7
2019	12