Year	Years
1970	0.87
1971	0.89
1972	0.92
1973	0.94
1974	0.97
1975	1
1976	1.03
1977	1.05
1978	1.08
1979	1.11
1980	1.14
1981	1.18
1982	1.21
1983	1.24
1984	1.28
1985	1.31
1986	1.35
1987	1.39
1988	1.42
1989	1.46
1990	1.51
1991	1.55
1992	1.59
1993	1.64
1994	1.68
1995	1.73
1996	1.78
1997	1.83
1998	1.88
1999	1.94
2000	1.99
2001	2.04
2002	2.1
2003	2.16
2004	2.22
2005	2.28
2006	2.34
2007	2.4
2008	2.46
2009	2.53
2010	2.59
2011	2.66
2012	2.73
2013	2.8
2014	2.87
2015	2.94