Year	Years
1970	1.1
1971	1.13
1972	1.16
1973	1.19
1974	1.22
1975	1.25
1976	1.29
1977	1.32
1978	1.36
1979	1.39
1980	1.43
1981	1.47
1982	1.51
1983	1.55
1984	1.59
1985	1.63
1986	1.67
1987	1.72
1988	1.76
1989	1.81
1990	1.85
1991	1.9
1992	1.95
1993	2
1994	2.05
1995	2.1
1996	2.16
1997	2.21
1998	2.27
1999	2.33
2000	2.39
2001	2.45
2002	2.51
2003	2.57
2004	2.63
2005	2.7
2006	2.76
2007	2.83
2008	2.9
2009	2.97
2010	3.04
2011	3.12
2012	3.19
2013	3.27
2014	3.34
2015	3.42