Year	Years
1970	1.03
1971	1.07
1972	1.1
1973	1.13
1974	1.16
1975	1.2
1976	1.23
1977	1.27
1978	1.3
1979	1.34
1980	1.38
1981	1.42
1982	1.46
1983	1.51
1984	1.55
1985	1.6
1986	1.64
1987	1.69
1988	1.74
1989	1.79
1990	1.84
1991	1.89
1992	1.95
1993	2
1994	2.06
1995	2.12
1996	2.18
1997	2.24
1998	2.3
1999	2.36
2000	2.42
2001	2.48
2002	2.55
2003	2.61
2004	2.67
2005	2.74
2006	2.81
2007	2.87
2008	2.94
2009	3.01
2010	3.08
2011	3.14
2012	3.21
2013	3.29
2014	3.36
2015	3.43