Year	Years
1970	1.3
1971	1.34
1972	1.37
1973	1.41
1974	1.44
1975	1.48
1976	1.52
1977	1.56
1978	1.6
1979	1.64
1980	1.68
1981	1.73
1982	1.77
1983	1.82
1984	1.86
1985	1.91
1986	1.96
1987	2.01
1988	2.06
1989	2.11
1990	2.17
1991	2.22
1992	2.27
1993	2.33
1994	2.39
1995	2.45
1996	2.51
1997	2.57
1998	2.63
1999	2.7
2000	2.76
2001	2.83
2002	2.9
2003	2.97
2004	3.04
2005	3.11
2006	3.18
2007	3.26
2008	3.34
2009	3.41
2010	3.49
2011	3.58
2012	3.66
2013	3.74
2014	3.83
2015	3.92