Year	% of population
1989	28.3
1990	27.1
1991	31.9
1992	29.4
1993	23.2
1994	20
1995	20.4
1996	21.5
1997	20.7
1998	19.7
1999	20.6
2000	20.6
2001	20.3
2002	20.6
2003	18.5
2004	21.7
2005	21.2
2006	20.2
2007	16.7
2008	17.7
2009	18.5
2011	24.8
2012	23.5
2013	23.3
2014	24.6
2015	23.6
2016	22.9
2017	22.1
2018	22.9
2019	23.9
2020	30
2021	26.2
2022	25.5