Year	% of population
2001	27.8
2002	27
2003	27.9
2004	27.9
2005	27.1
2006	24.8
2007	24.2
2008	24.9
2009	23.5
2010	21.3
2011	18.6
2012	18
2013	17.9
2014	17.1
2015	16
2016	14.9
2017	14.2
2018	13.8
2019	13.7
2020	16.2
2021	19.4