Year	Percent
1979	0.02051
1990	0.3
1991	0.3
1992	0.3
1993	0.3
1994	0.3
1995	0.3
1996	0.3
1997	0.3
1998	0.3
1999	0.3
2000	0.4
2001	0.4
2002	0.4
2003	0.4
2004	0.4
2005	0.4
2006	0.4
2007	0.4
2008	0.5
2009	0.4
2010	0.4
2011	0.4