Year	% of population
1989	58.3
1990	58.6
1991	57.6
1992	57.1
1993	57.3
1994	57
1995	56.6
1996	55.7
1997	55.2
1998	55
1999	55
2000	54.8
2001	54.1
2002	53.5
2003	52.4
2004	50.2
2005	48.9
2006	47.8
2007	46.6
2008	45.5
2009	45
2010	44.1
2011	43.2
2012	42.6
2013	42.1
2014	41.7
2015	41.7
2016	41.5
2017	41.2
2018	40.8
2019	40.8