Year	Years
1970	0.99
1971	1.03
1972	1.08
1973	1.12
1974	1.17
1975	1.22
1976	1.28
1977	1.33
1978	1.39
1979	1.45
1980	1.52
1981	1.58
1982	1.65
1983	1.73
1984	1.8
1985	1.88
1986	1.96
1987	2.05
1988	2.13
1989	2.23
1990	2.32
1991	2.42
1992	2.51
1993	2.61
1994	2.72
1995	2.82
1996	2.92
1997	3.02
1998	3.12
1999	3.23
2000	3.34
2001	3.44
2002	3.55
2003	3.67
2004	3.78
2005	3.89
2006	4.01
2007	4.12
2008	4.24
2009	4.36
2010	4.48
2011	4.6
2012	4.72
2013	4.84
2014	4.96
2015	5.09