Year	Years
1970	1.09
1971	1.12
1972	1.15
1973	1.18
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	1.61
1985	1.65
1986	1.7
1987	1.75
1988	1.8
1989	1.85
1990	1.91
1991	1.96
1992	2.02
1993	2.08
1994	2.14
1995	2.2
1996	2.27
1997	2.34
1998	2.41
1999	2.48
2000	2.55
2001	2.62
2002	2.7
2003	2.77
2004	2.85
2005	2.93
2006	3.01
2007	3.09
2008	3.17
2009	3.25
2010	3.34
2011	3.42
2012	3.51
2013	3.59
2014	3.68
2015	3.77