Year	Years
1970	0.95
1971	0.98
1972	1.02
1973	1.05
1974	1.08
1975	1.12
1976	1.16
1977	1.2
1978	1.24
1979	1.28
1980	1.33
1981	1.38
1982	1.42
1983	1.47
1984	1.53
1985	1.58
1986	1.64
1987	1.69
1988	1.75
1989	1.82
1990	1.88
1991	1.95
1992	2.01
1993	2.08
1994	2.15
1995	2.22
1996	2.28
1997	2.34
1998	2.41
1999	2.47
2000	2.54
2001	2.6
2002	2.67
2003	2.74
2004	2.81
2005	2.88
2006	2.95
2007	3.02
2008	3.1
2009	3.17
2010	3.25
2011	3.33
2012	3.41
2013	3.49
2014	3.57
2015	3.66