Year	% of population
2001	38.6
2002	37.5
2003	38
2004	37.4
2005	38.1
2006	38.6
2007	39.4
2008	40.2
2009	35.2
2010	30.2
2011	24.2
2012	23.8
2013	24.1
2014	25.5
2015	26.2
2016	26.1
2017	26
2018	26.8
2019	28.1
2020	29.8
2021	31.4