Year	Percent
1990	1.41
1991	1.48
1992	1.47
1993	1.37
1994	1.22
1995	1.06
1996	0.92
1997	0.81
1998	0.73
1999	0.67
2000	0.64
2001	0.62
2002	0.61
2003	0.6
2004	0.6
2005	0.6
2006	0.6
2007	0.59
2008	0.58
2009	0.6
2010	0.59
2011	0.59