Year	Years
1970	0.9
1971	0.93
1972	0.95
1973	0.98
1974	1.01
1975	1.03
1976	1.06
1977	1.09
1978	1.12
1979	1.15
1980	1.18
1981	1.21
1982	1.25
1983	1.28
1984	1.32
1985	1.35
1986	1.39
1987	1.43
1988	1.46
1989	1.5
1990	1.54
1991	1.59
1992	1.63
1993	1.67
1994	1.72
1995	1.76
1996	1.81
1997	1.85
1998	1.9
1999	1.95
2000	2
2001	2.05
2002	2.1
2003	2.16
2004	2.21
2005	2.27
2006	2.32
2007	2.38
2008	2.44
2009	2.5
2010	2.56
2011	2.63
2012	2.69
2013	2.76
2014	2.82
2015	2.89