Year	Years
1970	1.26
1971	1.29
1972	1.33
1973	1.36
1974	1.4
1975	1.43
1976	1.47
1977	1.5
1978	1.54
1979	1.58
1980	1.62
1981	1.66
1982	1.7
1983	1.74
1984	1.79
1985	1.83
1986	1.88
1987	1.92
1988	1.97
1989	2.02
1990	2.06
1991	2.11
1992	2.16
1993	2.22
1994	2.27
1995	2.32
1996	2.38
1997	2.44
1998	2.5
1999	2.56
2000	2.63
2001	2.69
2002	2.76
2003	2.83
2004	2.9
2005	2.97
2006	3.04
2007	3.11
2008	3.19
2009	3.27
2010	3.35
2011	3.43
2012	3.51
2013	3.59
2014	3.67
2015	3.76