Year	Age
1970	0.5
1971	0.6
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	1.1
1982	1.2
1983	1.3
1984	1.4
1985	1.6
1986	1.7
1987	1.8
1988	1.9
1989	2
1990	2.2
1991	2.3
1992	2.4
1993	2.6
1994	2.7
1995	2.8
1996	3
1997	3.1
1998	3.3
1999	3.4
2000	3.6
2001	3.7
2002	3.8
2003	4
2004	4.1
2005	4.3
2006	4.4
2007	4.5
2008	4.7
2009	4.8