Year	Age
1970	0.6
1971	0.6
1972	0.7
1973	0.7
1974	0.8
1975	0.8
1976	0.9
1977	0.9
1978	1
1979	1
1980	1.1
1981	1.2
1982	1.2
1983	1.3
1984	1.4
1985	1.5
1986	1.6
1987	1.6
1988	1.7
1989	1.8
1990	1.9
1991	1.9
1992	2
1993	2.1
1994	2.2
1995	2.3
1996	2.3
1997	2.4
1998	2.5
1999	2.6
2000	2.7
2001	2.8
2002	2.8
2003	2.9
2004	3
2005	3.1
2006	3.2
2007	3.2
2008	3.3
2009	3.4