Year	Years
1970	0.84
1971	0.86
1972	0.88
1973	0.91
1974	0.94
1975	0.96
1976	0.99
1977	1.02
1978	1.04
1979	1.07
1980	1.1
1981	1.13
1982	1.17
1983	1.2
1984	1.23
1985	1.27
1986	1.3
1987	1.34
1988	1.37
1989	1.41
1990	1.45
1991	1.49
1992	1.53
1993	1.58
1994	1.62
1995	1.66
1996	1.71
1997	1.76
1998	1.81
1999	1.86
2000	1.91
2001	1.96
2002	2.01
2003	2.07
2004	2.12
2005	2.18
2006	2.23
2007	2.29
2008	2.35
2009	2.41
2010	2.47
2011	2.53
2012	2.6
2013	2.66
2014	2.73
2015	2.8