Year	Years
1970	1.01
1971	1.05
1972	1.08
1973	1.12
1974	1.15
1975	1.19
1976	1.23
1977	1.27
1978	1.31
1979	1.36
1980	1.4
1981	1.45
1982	1.49
1983	1.54
1984	1.59
1985	1.64
1986	1.7
1987	1.75
1988	1.81
1989	1.86
1990	1.92
1991	1.98
1992	2.05
1993	2.11
1994	2.18
1995	2.24
1996	2.31
1997	2.38
1998	2.46
1999	2.53
2000	2.61
2001	2.69
2002	2.77
2003	2.85
2004	2.93
2005	3.02
2006	3.11
2007	3.19
2008	3.29
2009	3.38
2010	3.48
2011	3.57
2012	3.67
2013	3.77
2014	3.88
2015	3.98