Year	% of population
2001	18
2002	17.8
2003	16.9
2004	16
2005	14.9
2006	14
2007	12.9
2008	12.2
2009	14.1
2010	15.4
2011	16.4
2012	14.7
2013	13.5
2014	12.9
2015	12.9
2016	13.3
2017	13.3
2018	12.7
2019	12.5
2020	12.4
2021	12.9