Year	Percent
1990	9.59
1991	9.72
1992	9.47
1993	9.57
1994	9.41
1995	9.51
1996	8.69
1997	8.54
1998	8.33
1999	7.8
2000	7.6
2001	7.3
2002	7.71
2003	7.71
2004	7.36
2005	7.2
2006	7.52
2007	8.07
2008	8.03
2009	7.98
2010	8.02
2011	7.88
2012	8.07
2013	8.34
2014	8.7
2015	8.82
2016	8.65
2017	8.62
2018	8.47
2019	8.35