Year	Years
1970	0.35
1971	0.36
1972	0.37
1973	0.38
1974	0.39
1975	0.41
1976	0.42
1977	0.43
1978	0.44
1979	0.46
1980	0.47
1981	0.48
1982	0.5
1983	0.51
1984	0.53
1985	0.54
1986	0.56
1987	0.57
1988	0.59
1989	0.61
1990	0.63
1991	0.64
1992	0.66
1993	0.68
1994	0.7
1995	0.72
1996	0.75
1997	0.77
1998	0.79
1999	0.82
2000	0.84
2001	0.86
2002	0.89
2003	0.91
2004	0.94
2005	0.97
2006	0.99
2007	1.02
2008	1.05
2009	1.08
2010	1.11
2011	1.14
2012	1.17
2013	1.2
2014	1.24
2015	1.27