Year	Years
1970	1.06
1971	1.09
1972	1.12
1973	1.16
1974	1.19
1975	1.22
1976	1.26
1977	1.29
1978	1.33
1979	1.36
1980	1.4
1981	1.43
1982	1.47
1983	1.51
1984	1.54
1985	1.58
1986	1.62
1987	1.66
1988	1.69
1989	1.73
1990	1.77
1991	1.81
1992	1.84
1993	1.88
1994	1.91
1995	1.95
1996	1.99
1997	2.04
1998	2.09
1999	2.14
2000	2.2
2001	2.25
2002	2.31
2003	2.37
2004	2.44
2005	2.5
2006	2.57
2007	2.64
2008	2.71
2009	2.79
2010	2.87
2011	2.94
2012	3.03
2013	3.11
2014	3.2
2015	3.28