Year	% of population
2001	36.3
2002	37.5
2003	36.5
2004	34.8
2005	33.5
2006	32.5
2007	31.3
2008	29.5
2009	30.6
2010	33.2
2011	35.8
2012	36.7
2013	36.6
2014	36.8
2015	35.9
2016	35.3
2017	35.1
2018	35.6
2019	36.9
2020	37.8
2021	38.4