Year	% of population
1979	21.6
1986	20.7
1992	18.5
1997	21.7
2001	22.5
2002	23.5
2003	24.5
2004	25.5
2005	25.5
2006	25
2007	25.2
2008	24.5
2009	26.2
2010	25.5
2011	25.2
2012	24.7
2013	22.7
2014	23.7
2015	22.7
2016	23.2
2017	22.5
2018	22.5
2019	22.5
2020	22
2021	22.2