Year	Years
1970	0.85
1971	0.87
1972	0.9
1973	0.93
1974	0.96
1975	0.99
1976	1.03
1977	1.06
1978	1.09
1979	1.13
1980	1.17
1981	1.21
1982	1.25
1983	1.3
1984	1.34
1985	1.39
1986	1.44
1987	1.5
1988	1.55
1989	1.61
1990	1.68
1991	1.74
1992	1.82
1993	1.89
1994	1.98
1995	2.07
1996	2.14
1997	2.21
1998	2.28
1999	2.35
2000	2.42
2001	2.49
2002	2.57
2003	2.64
2004	2.72
2005	2.79
2006	2.87
2007	2.95
2008	3.03
2009	3.11
2010	3.2
2011	3.28
2012	3.37
2013	3.45
2014	3.54
2015	3.63