Year	Percent
1987	0.0104
1990	0.1
1991	0.1
1992	0.1
1993	0.1
1994	0.1
1995	0.1
1996	0.1
1997	0.2
1998	0.2
1999	0.2
2000	0.2
2001	0.3
2002	0.3
2003	0.3
2004	0.4
2005	0.4
2006	0.5
2007	0.6
2008	0.6
2009	0.7
2010	0.7
2011	0.7