Year	% of population
2004	16.1
2005	15.6
2006	15.5
2007	15.9
2008	15.8
2009	15.6
2010	14.8
2011	14.7
2012	15.3
2013	14.4
2014	16.2
2015	16.1
2016	15.7
2017	15.4
2018	14.7
2019	14.3
2020	13.8
2021	13.9