Year	Percent
1990	49.1
1991	49.5
1992	49.5
1993	49.6
1994	50.2
1995	50.2
1996	50.2
1997	52.3
1998	52.3
1999	56.3
2000	56.42
2001	56.42
2002	56.42
2003	56.9
2004	56.9
2005	61.89
2006	61.89
2007	61.98
2008	62.04
2009	70.32