Year	% of population
1980	22.4
1986	21.4
1987	21.9
1991	22.2
1992	24.1
1993	24
1994	24.7
1995	26.6
1996	27.3
1997	28.2
1998	28.2
1999	28.8
2000	30.9
2001	31.5
2002	34.3
2003	30.1
2004	29.6
2005	28.3
2006	27.2
2007	27.7
2008	26.1
2009	25.8
2010	25.5
2011	24.3
2012	23.7
2013	24
2014	23.8
2016	24.1
2017	23
2018	23.9
2019	25
2020	26
2021	23.8
2022	22.8