Year	Age
1970	5.8
1971	5.9
1972	6.1
1973	6.3
1974	6.4
1975	6.6
1976	6.7
1977	6.9
1978	7
1979	7.2
1980	7.3
1981	7.5
1982	7.6
1983	7.8
1984	7.9
1985	8
1986	8.1
1987	8.3
1988	8.4
1989	8.5
1990	8.6
1991	8.7
1992	8.8
1993	8.9
1994	9
1995	9.1
1996	9.2
1997	9.3
1998	9.4
1999	9.5
2000	9.6
2001	9.7
2002	9.8
2003	9.9
2004	10
2005	10.1
2006	10.2
2007	10.3
2008	10.3
2009	10.4