Year	Years
1970	0.27
1971	0.28
1972	0.29
1973	0.3
1974	0.31
1975	0.32
1976	0.34
1977	0.35
1978	0.36
1979	0.37
1980	0.38
1981	0.4
1982	0.41
1983	0.42
1984	0.44
1985	0.45
1986	0.47
1987	0.48
1988	0.5
1989	0.52
1990	0.53
1991	0.55
1992	0.57
1993	0.59
1994	0.61
1995	0.63
1996	0.65
1997	0.67
1998	0.69
1999	0.71
2000	0.74
2001	0.76
2002	0.79
2003	0.81
2004	0.84
2005	0.87
2006	0.89
2007	0.92
2008	0.95
2009	0.98
2010	1.02
2011	1.05
2012	1.08
2013	1.12
2014	1.15
2015	1.19