Year	Age
1970	1.5
1971	1.5
1972	1.6
1973	1.7
1974	1.8
1975	1.9
1976	2
1977	2.1
1978	2.2
1979	2.3
1980	2.4
1981	2.5
1982	2.6
1983	2.7
1984	2.8
1985	2.9
1986	3
1987	3.1
1988	3.2
1989	3.3
1990	3.4
1991	3.5
1992	3.6
1993	3.7
1994	3.8
1995	3.9
1996	4
1997	4.1
1998	4.2
1999	4.3
2000	4.4
2001	4.5
2002	4.6
2003	4.8
2004	4.9
2005	5
2006	5.1
2007	5.2
2008	5.3
2009	5.4