Year	Percent
1980	0.01252
1990	0.6
1991	1
1992	1.6
1993	2.5
1994	3.4
1995	4.2
1996	4.8
1997	5.1
1998	5.3
1999	5.4
2000	5.5
2001	5.5
2002	5.5
2003	5.5
2004	5.4
2005	5.4
2006	5.4
2007	5.4
2008	5.3
2009	4.8
2010	4.7
2011	4.6