Year	% of population
1997	33.8
1998	39.3
1999	44.4
2000	42.8
2001	39.8
2002	34.2
2003	28.5
2004	29.5
2005	31.9
2006	24
2007	22.3
2008	20.8
2009	21.2
2010	18.5
2011	17
2012	16.1
2013	15.1
2014	13.2
2015	12.5
2016	11.4
2017	12
2018	10.5
2019	11.4
2021	11.2