Year	Years
1970	0.89
1971	0.92
1972	0.96
1973	0.99
1974	1.03
1975	1.07
1976	1.11
1977	1.15
1978	1.19
1979	1.24
1980	1.29
1981	1.34
1982	1.39
1983	1.44
1984	1.5
1985	1.55
1986	1.61
1987	1.68
1988	1.74
1989	1.81
1990	1.88
1991	1.95
1992	2.03
1993	2.11
1994	2.19
1995	2.28
1996	2.38
1997	2.47
1998	2.57
1999	2.67
2000	2.78
2001	2.88
2002	2.98
2003	3.09
2004	3.2
2005	3.31
2006	3.42
2007	3.53
2008	3.64
2009	3.75
2010	3.86
2011	3.97
2012	4.09
2013	4.2
2014	4.31
2015	4.43