Year	Years
1970	0.39
1971	0.4
1972	0.41
1973	0.42
1974	0.43
1975	0.44
1976	0.46
1977	0.47
1978	0.48
1979	0.5
1980	0.51
1981	0.53
1982	0.54
1983	0.56
1984	0.57
1985	0.59
1986	0.6
1987	0.62
1988	0.64
1989	0.66
1990	0.68
1991	0.7
1992	0.72
1993	0.74
1994	0.76
1995	0.78
1996	0.81
1997	0.83
1998	0.86
1999	0.89
2000	0.91
2001	0.94
2002	0.97
2003	1
2004	1.03
2005	1.06
2006	1.09
2007	1.12
2008	1.15
2009	1.18
2010	1.22
2011	1.25
2012	1.29
2013	1.32
2014	1.36
2015	1.4