Year	Years
1990	69.8
1991	70.1
1992	70.2
1993	70.2
1994	70.5
1995	71.2
1996	71.8
1997	71.9
1998	71.9
1999	72.4
2000	72.9
2001	73.2
2002	73.8
2003	73.8
2004	73.6
2005	73.4
2006	73.4
2007	73.7
2008	74.1
2009	74
2010	73.8
2011	73.7
2012	73.8
2013	73.9