Year	Years
1970	0.22
1971	0.23
1972	0.24
1973	0.25
1974	0.25
1975	0.26
1976	0.28
1977	0.29
1978	0.3
1979	0.31
1980	0.32
1981	0.33
1982	0.35
1983	0.36
1984	0.38
1985	0.39
1986	0.41
1987	0.43
1988	0.44
1989	0.46
1990	0.48
1991	0.5
1992	0.53
1993	0.55
1994	0.57
1995	0.6
1996	0.62
1997	0.65
1998	0.67
1999	0.7
2000	0.72
2001	0.75
2002	0.77
2003	0.8
2004	0.83
2005	0.86
2006	0.89
2007	0.92
2008	0.95
2009	0.98
2010	1.02
2011	1.05
2012	1.09
2013	1.12
2014	1.16
2015	1.2