Year	Years
1970	1.1
1971	1.13
1972	1.17
1973	1.2
1974	1.23
1975	1.26
1976	1.3
1977	1.33
1978	1.37
1979	1.41
1980	1.44
1981	1.48
1982	1.52
1983	1.56
1984	1.61
1985	1.65
1986	1.69
1987	1.74
1988	1.79
1989	1.83
1990	1.88
1991	1.93
1992	1.98
1993	2.04
1994	2.09
1995	2.15
1996	2.21
1997	2.26
1998	2.32
1999	2.38
2000	2.45
2001	2.51
2002	2.57
2003	2.64
2004	2.71
2005	2.78
2006	2.85
2007	2.92
2008	2.99
2009	3.06
2010	3.14
2011	3.22
2012	3.29
2013	3.37
2014	3.45
2015	3.54