Year	Years
1990	71.4
1991	71.3
1992	71.2
1993	71
1994	70.8
1995	70.9
1996	70.8
1997	70.7
1998	71.1
1999	71.4
2000	71.7
2001	71.9
2002	72.2
2003	72.4
2004	72.4
2005	72.5
2006	72.7
2007	72.9
2008	73.2
2009	73.3
2010	73.6
2011	74
2012	74.3
2013	74.5