Year	% of population
2004	14.3
2005	14.2
2006	15.1
2007	15.3
2008	14.9
2009	15.5
2010	15.6
2011	15.1
2012	15.8
2013	15.8
2014	16.6
2015	16.5
2016	16.7
2017	16.8
2018	17.1
2019	16.9
2020	16.9
2021	16.7