Year	Age
1970	1.4
1971	1.4
1972	1.5
1973	1.6
1974	1.7
1975	1.8
1976	1.9
1977	2
1978	2.1
1979	2.3
1980	2.4
1981	2.5
1982	2.7
1983	2.8
1984	3
1985	3.1
1986	3.3
1987	3.4
1988	3.5
1989	3.7
1990	3.8
1991	4
1992	4.1
1993	4.3
1994	4.4
1995	4.5
1996	4.7
1997	4.8
1998	5
1999	5.1
2000	5.3
2001	5.4
2002	5.6
2003	5.7
2004	5.8
2005	6
2006	6.1
2007	6.2
2008	6.4
2009	6.5