Year	Years
1970	1.14
1971	1.18
1972	1.22
1973	1.26
1974	1.31
1975	1.35
1976	1.4
1977	1.45
1978	1.5
1979	1.55
1980	1.61
1981	1.67
1982	1.73
1983	1.79
1984	1.85
1985	1.92
1986	1.99
1987	2.06
1988	2.14
1989	2.21
1990	2.3
1991	2.38
1992	2.47
1993	2.56
1994	2.65
1995	2.75
1996	2.85
1997	2.95
1998	3.06
1999	3.16
2000	3.27
2001	3.38
2002	3.49
2003	3.6
2004	3.72
2005	3.84
2006	3.96
2007	4.08
2008	4.2
2009	4.32
2010	4.45
2011	4.58
2012	4.7
2013	4.83
2014	4.96
2015	5.09