Year	Years
1970	1.04
1971	1.08
1972	1.11
1973	1.15
1974	1.19
1975	1.23
1976	1.27
1977	1.31
1978	1.35
1979	1.39
1980	1.44
1981	1.49
1982	1.54
1983	1.59
1984	1.64
1985	1.69
1986	1.74
1987	1.8
1988	1.86
1989	1.92
1990	1.98
1991	2.04
1992	2.11
1993	2.18
1994	2.25
1995	2.32
1996	2.39
1997	2.47
1998	2.55
1999	2.63
2000	2.71
2001	2.8
2002	2.88
2003	2.97
2004	3.06
2005	3.16
2006	3.25
2007	3.35
2008	3.45
2009	3.55
2010	3.65
2011	3.75
2012	3.86
2013	3.97
2014	4.08
2015	4.19