Year	Age
1970	0.7
1971	0.7
1972	0.8
1973	0.8
1974	0.9
1975	0.9
1976	1
1977	1
1978	1.1
1979	1.2
1980	1.3
1981	1.4
1982	1.4
1983	1.5
1984	1.6
1985	1.7
1986	1.8
1987	1.9
1988	2
1989	2.1
1990	2.2
1991	2.3
1992	2.4
1993	2.5
1994	2.6
1995	2.7
1996	2.8
1997	2.9
1998	3
1999	3.1
2000	3.3
2001	3.4
2002	3.5
2003	3.6
2004	3.7
2005	3.8
2006	4
2007	4.1
2008	4.2
2009	4.3