Year	Percent
1990	0.56
1991	0.74
1992	0.97
1993	1.28
1994	1.64
1995	2.07
1996	2.5
1997	2.71
1998	2.72
1999	2.64
2000	2.53
2001	2.39
2002	1.94
2003	1.56
2004	1.36
2005	1.17
2006	1.01
2007	0.91
2008	0.86
2009	0.84
2010	0.84
2011	0.77