Year	Years
1990	72.1
1991	72.4
1992	72.6
1993	72.8
1994	72.8
1995	72.8
1996	73.1
1997	73.2
1998	73.4
1999	73.4
2000	73.8
2001	74
2002	74.1
2003	74.1
2004	74.2
2005	74.4
2006	74.6
2007	74.6
2008	74.5
2009	74.3
2010	74.3
2011	74.4
2012	74.5
2013	74.7