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	1.1
1980	1.1
1981	1.2
1982	1.3
1983	1.4
1984	1.4
1985	1.5
1986	1.6
1987	1.7
1988	1.8
1989	1.9
1990	2
1991	2.1
1992	2.2
1993	2.3
1994	2.4
1995	2.5
1996	2.6
1997	2.7
1998	2.8
1999	2.9
2000	3
2001	3.1
2002	3.3
2003	3.4
2004	3.5
2005	3.6
2006	3.7
2007	3.9
2008	4
2009	4.1