Year	% of population
2001	18.3
2002	19.9
2003	21.4
2004	22
2005	21.4
2006	19.4
2007	17.2
2008	16.2
2009	16
2010	15.7
2011	15.4
2012	14.8
2013	14.6
2014	14.4
2015	14
2016	13.5
2017	12.9
2018	13.1
2019	14.4
2020	15.9
2021	16.6