Year	% of population
2000	17.9
2001	17.3
2002	17
2003	16.7
2004	16.5
2005	16.4
2006	16.4
2007	16.7
2008	16.9
2009	17.5
2010	18.3
2011	19.3
2012	20.6
2013	21.6
2014	23.3
2015	25.1
2016	27.3
2017	29.6
2018	32.1
2019	34.7
2020	37.4
2021	40.3
2022	42.6