Year	Years
1990	71.5
1991	70.7
1992	69.8
1993	69
1994	68.5
1995	68.9
1996	70
1997	71
1998	71.7
1999	72
2000	72
2001	71.9
2002	72
2003	72.1
2004	71.9
2005	71.5
2006	71.1
2007	71.2
2008	72
2009	73.1
2010	73.9
2011	74.5
2012	74.8
2013	75