Year	Years
1990	48.8
1991	49.1
1992	49.4
1993	49.7
1994	49.7
1995	49.9
1996	50
1997	50.1
1998	50.3
1999	50.7
2000	51.1
2001	51.6
2002	52.2
2003	52.9
2004	53.5
2005	54.2
2006	54.8
2007	55.3
2008	55.8
2009	56.2
2010	56.5
2011	56.8
2012	57
2013	57.2
