Year	Years
1970	0.29
1971	0.3
1972	0.31
1973	0.32
1974	0.33
1975	0.34
1976	0.35
1977	0.37
1978	0.38
1979	0.39
1980	0.41
1981	0.42
1982	0.43
1983	0.45
1984	0.46
1985	0.48
1986	0.5
1987	0.51
1988	0.53
1989	0.55
1990	0.57
1991	0.59
1992	0.61
1993	0.63
1994	0.65
1995	0.67
1996	0.69
1997	0.72
1998	0.74
1999	0.76
2000	0.79
2001	0.82
2002	0.84
2003	0.87
2004	0.9
2005	0.93
2006	0.95
2007	0.98
2008	1.02
2009	1.05
2010	1.08
2011	1.11
2012	1.15
2013	1.18
2014	1.22
2015	1.25