Year	% of population
1981	35.5
1982	35.9
1983	37.3
1984	37
1985	36.5
1986	34.2
1987	35.4
1988	35.5
1989	35.2
1990	35.7
1991	35.2
1992	35.1
1993	35.6
1994	35.1
1995	34.7
1996	35.6
1997	35.4
1998	35.1
1999	35.3
2000	34.5
2001	34.3
2002	34
2003	33.7
2004	33.1
2005	32.7
2006	31.6
2007	31
2008	30.5
2009	30.1
2010	29.3
2011	28.8
2012	28.7
2013	28.1
2014	27.7
2015	27.4
2016	27.6
2017	27.4
2018	27.1
2019	27.2
2020	25.7
2021	27.1
2022	26