Year	% of population
2001	14.9
2002	13.5
2003	12.7
2004	12.1
2005	11.1
2006	10.4
2007	9.2
2008	8.1
2009	6.6
2010	6.2
2011	6.3
2012	6.6
2013	6.9
2014	7.5
2015	8.2
2016	8.3
2017	7.6
2018	6.5
2019	5.7
2020	5.1
2021	4.9