Year	Years
1990	60.3
1991	60.6
1992	60.8
1993	60.7
1994	60.5
1995	60.7
1996	60.6
1997	60.4
1998	60.3
1999	60.3
2000	60.2
2001	60.3
2002	60.5
2003	60.8
2004	61.1
2005	61.5
2006	61.8
2007	62.3
2008	62.7
2009	63.1
2010	63.5
2011	64
2012	64.6
2013	64.9