Year	% of population
2001	21.7
2002	21.1
2003	19.9
2004	19.2
2005	17.8
2006	17.8
2007	17.7
2008	16.9
2009	15.9
2010	14.7
2011	15.1
2012	15.7
2013	16.4
2014	16.8
2015	17.3
2016	17.6
2017	17.5
2018	17.2
2019	16.9
2020	16.4
2021	16.3