Year	% of population
1990	58.7
1991	59.8
1992	60.5
1993	61.2
1994	61.8
1995	61.5
1996	60.9
1997	60.5
1998	60.2
1999	59.9
2000	59.5
2001	58.8
2002	58.1
2003	57.2
2004	55.5
2005	54.5
2006	53.5
2007	52.7
2008	51.7
2009	51.5
2010	50.4
2011	49.6
2012	48.8
2013	48.2
2014	47.8
2015	47.8
2016	47.9
2017	47.8
2018	47.6
2019	47.5