Year	Years
1990	67.9
1991	67.6
1992	66.9
1993	65.8
1994	64.2
1995	62.3
1996	60.2
1997	57.9
1998	55.6
1999	53.5
2000	51.6
2001	50.2
2002	49.3
2003	49.4
2004	51
2005	54.3
2006	57.5
2007	60.1
2008	61.2
2009	62.6
2010	64.5
2011	65.7
2012	65.5
2013	65.8