Year	Years
1970	0.22
1971	0.23
1972	0.23
1973	0.24
1974	0.25
1975	0.26
1976	0.27
1977	0.28
1978	0.3
1979	0.31
1980	0.32
1981	0.33
1982	0.34
1983	0.36
1984	0.37
1985	0.39
1986	0.4
1987	0.42
1988	0.43
1989	0.45
1990	0.47
1991	0.48
1992	0.5
1993	0.52
1994	0.54
1995	0.56
1996	0.58
1997	0.6
1998	0.62
1999	0.64
2000	0.67
2001	0.69
2002	0.71
2003	0.74
2004	0.76
2005	0.78
2006	0.81
2007	0.83
2008	0.86
2009	0.88
2010	0.91
2011	0.94
2012	0.96
2013	0.99
2014	1.02
2015	1.05