Year	Years
1970	1.17
1971	1.21
1972	1.26
1973	1.31
1974	1.36
1975	1.41
1976	1.46
1977	1.52
1978	1.58
1979	1.64
1980	1.7
1981	1.77
1982	1.84
1983	1.91
1984	1.99
1985	2.07
1986	2.15
1987	2.24
1988	2.33
1989	2.43
1990	2.53
1991	2.64
1992	2.75
1993	2.87
1994	2.99
1995	3.12
1996	3.24
1997	3.35
1998	3.47
1999	3.59
2000	3.71
2001	3.83
2002	3.95
2003	4.07
2004	4.19
2005	4.32
2006	4.45
2007	4.58
2008	4.71
2009	4.84
2010	4.97
2011	5.1
2012	5.24
2013	5.37
2014	5.51
2015	5.65