Year	% of population
2001	15.6
2002	14.8
2003	14.4
2004	13.9
2005	13.7
2006	13.2
2007	13.2
2008	12.9
2009	14.4
2010	15.2
2011	16.1
2012	15.8
2013	15.6
2014	14.8
2015	14.8
2016	14.3
2017	13.6
2018	12.7
2019	11.8
2020	11.7
2021	11.2