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