Year	Years
1970	1.1
1971	1.13
1972	1.16
1973	1.19
1974	1.22
1975	1.25
1976	1.29
1977	1.32
1978	1.36
1979	1.4
1980	1.44
1981	1.48
1982	1.52
1983	1.56
1984	1.6
1985	1.64
1986	1.69
1987	1.73
1988	1.78
1989	1.83
1990	1.88
1991	1.93
1992	1.98
1993	2.04
1994	2.09
1995	2.15
1996	2.21
1997	2.27
1998	2.33
1999	2.39
2000	2.46
2001	2.52
2002	2.59
2003	2.65
2004	2.72
2005	2.79
2006	2.86
2007	2.93
2008	3.01
2009	3.08
2010	3.16
2011	3.23
2012	3.31
2013	3.39
2014	3.47
2015	3.56