Year	Years
1970	1.06
1971	1.09
1972	1.12
1973	1.15
1974	1.18
1975	1.21
1976	1.25
1977	1.28
1978	1.32
1979	1.35
1980	1.39
1981	1.43
1982	1.46
1983	1.5
1984	1.54
1985	1.59
1986	1.63
1987	1.67
1988	1.72
1989	1.76
1990	1.81
1991	1.86
1992	1.91
1993	1.96
1994	2.01
1995	2.07
1996	2.12
1997	2.17
1998	2.23
1999	2.29
2000	2.35
2001	2.41
2002	2.47
2003	2.53
2004	2.59
2005	2.66
2006	2.73
2007	2.79
2008	2.86
2009	2.93
2010	3.01
2011	3.08
2012	3.16
2013	3.23
2014	3.31
2015	3.39