Year	Years
1970	1.02
1971	1.07
1972	1.12
1973	1.18
1974	1.24
1975	1.3
1976	1.37
1977	1.45
1978	1.52
1979	1.61
1980	1.69
1981	1.79
1982	1.89
1983	1.99
1984	2.11
1985	2.23
1986	2.35
1987	2.49
1988	2.63
1989	2.78
1990	2.94
1991	3.11
1992	3.28
1993	3.46
1994	3.65
1995	3.83
1996	3.97
1997	4.12
1998	4.26
1999	4.4
2000	4.54
2001	4.68
2002	4.82
2003	4.97
2004	5.11
2005	5.26
2006	5.4
2007	5.55
2008	5.7
2009	5.85
2010	6
2011	6.15
2012	6.3
2013	6.45
2014	6.61
2015	6.76