Year	Age
1970	0.5
1971	0.5
1972	0.6
1973	0.6
1974	0.7
1975	0.7
1976	0.8
1977	0.8
1978	0.9
1979	0.9
1980	1
1981	1
1982	1.1
1983	1.2
1984	1.2
1985	1.3
1986	1.4
1987	1.5
1988	1.6
1989	1.7
1990	1.7
1991	1.8
1992	1.9
1993	2
1994	2.2
1995	2.3
1996	2.4
1997	2.5
1998	2.6
1999	2.8
2000	2.9
2001	3
2002	3.2
2003	3.3
2004	3.4
2005	3.6
2006	3.7
2007	3.9
2008	4
2009	4.2