Year	Age
1970	1.3
1971	1.4
1972	1.5
1973	1.6
1974	1.6
1975	1.7
1976	1.8
1977	1.9
1978	2
1979	2.1
1980	2.2
1981	2.3
1982	2.4
1983	2.5
1984	2.6
1985	2.7
1986	2.8
1987	2.9
1988	3
1989	3.1
1990	3.2
1991	3.4
1992	3.5
1993	3.6
1994	3.7
1995	3.9
1996	4
1997	4.1
1998	4.2
1999	4.4
2000	4.5
2001	4.6
2002	4.8
2003	4.9
2004	5
2005	5.2
2006	5.3
2007	5.4
2008	5.6
2009	5.7