Year	Years
1990	71.3
1991	71.5
1992	71.8
1993	72
1994	72.1
1995	72.2
1996	72.2
1997	72.3
1998	72.3
1999	72.6
2000	72.7
2001	72.7
2002	72.6
2003	72.4
2004	72
2005	72.1
2006	72.2
2007	72.2
2008	72.5
2009	72.7
2010	73.1
2011	73.3
2012	73.5
2013	73.6