Year	Percent
1990	1.34
1991	1.19
1992	1.04
1993	0.91
1994	0.79
1995	0.7
1996	0.64
1997	0.62
1998	0.62
1999	0.63
2000	0.66
2001	0.69
2002	0.72
2003	0.78
2004	0.81
2005	0.82
2006	0.83
2007	0.87
2008	0.89
2009	0.9
2010	0.88
2011	0.84