Year	Years
1990	50.3
1991	50.2
1992	50.4
1993	50.5
1994	50.1
1995	50.4
1996	50.6
1997	50.7
1998	50
1999	50.8
2000	51
2001	51.1
2002	51.6
2003	52.1
2004	52.5
2005	52.9
2006	53.2
2007	53.6
2008	54
2009	54.5
2010	54.8
2011	55.2
2012	55.5
2013	56.2