Year	Percent
1984	0.01215
1990	0.2
1991	0.3
1992	0.4
1993	0.5
1994	0.6
1995	0.6
1996	0.7
1997	0.8
1998	0.8
1999	0.9
2000	0.9
2001	0.8
2002	0.8
2003	0.8
2004	0.7
2005	0.7
2006	0.6
2007	0.6
2008	0.5
2009	0.5
2010	0.5
2011	0.5