Year	Years
1970	1.02
1971	1.06
1972	1.09
1973	1.13
1974	1.17
1975	1.2
1976	1.24
1977	1.28
1978	1.32
1979	1.37
1980	1.41
1981	1.46
1982	1.5
1983	1.55
1984	1.6
1985	1.65
1986	1.71
1987	1.76
1988	1.82
1989	1.87
1990	1.93
1991	2
1992	2.06
1993	2.12
1994	2.19
1995	2.26
1996	2.34
1997	2.41
1998	2.49
1999	2.57
2000	2.65
2001	2.73
2002	2.82
2003	2.91
2004	2.99
2005	3.08
2006	3.18
2007	3.27
2008	3.37
2009	3.47
2010	3.57
2011	3.67
2012	3.78
2013	3.88
2014	3.99
2015	4.1