Year	Years
1970	9.12
1971	9.27
1972	9.42
1973	9.57
1974	9.72
1975	9.87
1976	10.02
1977	10.17
1978	10.32
1979	10.47
1980	10.62
1981	10.76
1982	10.91
1983	11.05
1984	11.2
1985	11.34
1986	11.48
1987	11.62
1988	11.76
1989	11.9
1990	12.03
1991	12.17
1992	12.3
1993	12.43
1994	12.57
1995	12.7
1996	12.85
1997	13
1998	13.15
1999	13.29
2000	13.44
2001	13.59
2002	13.73
2003	13.87
2004	14.01
2005	14.15
2006	14.29
2007	14.43
2008	14.56
2009	14.69
2010	14.82
2011	14.95
2012	15.08
2013	15.2
2014	15.33
2015	15.45