Year	Years
1970	1.16
1971	1.2
1972	1.24
1973	1.29
1974	1.33
1975	1.38
1976	1.43
1977	1.48
1978	1.53
1979	1.58
1980	1.64
1981	1.7
1982	1.76
1983	1.82
1984	1.88
1985	1.95
1986	2.02
1987	2.09
1988	2.16
1989	2.24
1990	2.32
1991	2.4
1992	2.49
1993	2.57
1994	2.66
1995	2.76
1996	2.86
1997	2.96
1998	3.06
1999	3.17
2000	3.27
2001	3.38
2002	3.49
2003	3.6
2004	3.71
2005	3.82
2006	3.94
2007	4.06
2008	4.17
2009	4.29
2010	4.41
2011	4.53
2012	4.65
2013	4.77
2014	4.9
2015	5.02