Year	Years
1970	0.99
1971	1.04
1972	1.09
1973	1.14
1974	1.2
1975	1.27
1976	1.34
1977	1.41
1978	1.49
1979	1.58
1980	1.67
1981	1.76
1982	1.87
1983	1.99
1984	2.11
1985	2.24
1986	2.38
1987	2.54
1988	2.7
1989	2.87
1990	3.06
1991	3.25
1992	3.46
1993	3.67
1994	3.88
1995	4.1
1996	4.25
1997	4.41
1998	4.57
1999	4.73
2000	4.89
2001	5.05
2002	5.21
2003	5.37
2004	5.53
2005	5.69
2006	5.85
2007	6.01
2008	6.17
2009	6.33
2010	6.49
2011	6.65
2012	6.81
2013	6.97
2014	7.13
2015	7.29