Year	Years
1970	0.3
1971	0.3
1972	0.3
1973	0.3
1974	0.4
1975	0.4
1976	0.4
1977	0.4
1978	0.5
1979	0.5
1980	0.5
1981	0.6
1982	0.6
1983	0.7
1984	0.7
1985	0.8
1986	0.8
1987	0.9
1988	0.9
1989	1
1990	1
1991	1.1
1992	1.1
1993	1.2
1994	1.3
1995	1.3
1996	1.4
1997	1.5
1998	1.5
1999	1.6
2000	1.7
2001	1.8
2002	1.9
2003	2
2004	2.1
2005	2.1
2006	2.2
2007	2.3
2008	2.4
2009	2.5