Year	Percent
1990	2.35
1991	2.9
1992	3.23
1993	4.19
1994	4.64
1995	4.8
1996	4.86
1997	4.78
1998	4.51
1999	4.1
2000	3.78
2001	3.48
2002	3.06
2003	2.7
2004	2.19
2005	2
2006	1.88
2007	1.78
2008	1.65
2009	1.15
2010	1.07
2011	1