Year	Age
1970	0.8
1971	0.9
1972	0.9
1973	1
1974	1
1975	1.1
1976	1.2
1977	1.3
1978	1.4
1979	1.4
1980	1.5
1981	1.7
1982	1.8
1983	1.9
1984	2
1985	2.1
1986	2.3
1987	2.4
1988	2.5
1989	2.7
1990	2.8
1991	2.9
1992	3.1
1993	3.2
1994	3.4
1995	3.5
1996	3.7
1997	3.8
1998	4
1999	4.1
2000	4.3
2001	4.5
2002	4.6
2003	4.8
2004	4.9
2005	5.1
2006	5.3
2007	5.4
2008	5.6
2009	5.7