Year	% of population
2001	46.4
2002	44.1
2003	39
2004	36.3
2005	34.5
2006	31.9
2007	28.6
2008	25.4
2009	22.2
2010	20.5
2011	19.7
2012	21
2013	20.8
2014	20.7
2015	21.3
2016	21.8
2017	22.7
2018	24
2019	26.9
2020	28.8
2021	30.1