Year	Age
1970	1.2
1971	1.3
1972	1.4
1973	1.4
1974	1.5
1975	1.6
1976	1.7
1977	1.8
1978	1.9
1979	2
1980	2.2
1981	2.3
1982	2.4
1983	2.6
1984	2.7
1985	2.8
1986	3
1987	3.1
1988	3.3
1989	3.4
1990	3.5
1991	3.7
1992	3.8
1993	4
1994	4.1
1995	4.3
1996	4.5
1997	4.6
1998	4.8
1999	4.9
2000	5.1
2001	5.2
2002	5.4
2003	5.5
2004	5.7
2005	5.8
2006	6
2007	6.1
2008	6.2
2009	6.4