Year	% of population
1981	60
1982	58.9
1983	57.1
1984	56.1
1985	55.4
1986	54.8
1987	54.4
1988	53.7
1989	53.5
1990	53.3
1991	52.1
1992	51.2
1993	50.9
1994	50.2
1995	49.8
1996	49.1
2002	48.1
2003	47.4
2004	46.5
2005	45.6
2006	44.8
2007	44
2008	43.4
2009	42.7
2010	40.7
2011	38.9
2012	38
2013	37.2
2014	36.6
2015	35.9
2016	35.3
2017	33.6
2018	31.7
2019	32.2
2020	33.3
2021	32.1
2022	31