Year	Years
1990	57.2
1991	56.8
1992	56.4
1993	55.9
1994	55.5
1995	55.1
1996	54.8
1997	54.6
1998	54.5
1999	54.5
2000	54.8
2001	55.1
2002	55.6
2003	56.2
2004	56.7
2005	57.2
2006	57.9
2007	58.7
2008	59.7
2009	60.3
2010	60.9
2011	61.4
2012	61.6
2013	62.2