Year	Years
1990	64.3
1991	64.3
1992	64.3
1993	64.3
1994	64.3
1995	64.3
1996	64.2
1997	64.1
1998	64
1999	63.9
2000	63.8
2001	63.7
2002	63.6
2003	63.6
2004	63.5
2005	63.5
2006	63.5
2007	63.6
2008	63.7
2009	63.9
2010	64.1
2011	64.3
2012	64.5
2013	64.7