Year	% of population
2001	32.8
2002	33.7
2003	32.2
2004	31.3
2005	28.1
2006	25.6
2007	25.4
2008	25.6
2009	25.6
2010	23.8
2011	21.7
2012	20.7
2013	20.3
2014	20.2
2015	20.5
2016	21.1
2017	21.8
2018	22.2
2019	22.3
2020	22.2
2021	23.5