Year	%
1963	43.5
1964	44
1965	43.4
1966	43.6
1967	43
1968	42.6
1969	42.4
1970	42.8
1971	43.1
1972	42.7
1973	42.3
1974	41.8
1975	41.9
1976	41.8
1977	41.8
1978	41.1
1979	41.2
1980	41.2
1981	41.8
1982	42.6
1983	42.9
1984	43
1985	43.3
1986	43.2
1987	42.9
1988	43.4
1989	44
1990	44
1991	43.8
1992	44
1993	45.8
1994	45.6
1995	45.6
1996	45.9
1997	46.2
1998	45.6
1999	45.7
2000	45.9
2001	46.2
2002	45.9
2003	46.2
2004	45.8
2005	46.5
2006	46.9
2007	46.3
2008	46.2
2009	46.2
2010	45.6
2011	46.4
2012	46.4
2013	46.2
2014	47.2
2015	46.9
2016	46.7
2017	46.6
2018	46.9
2019	47
2020	45.5
2021	46.1