Year	Percent
1991	10.296
1992	10.284
1993	10.25
1994	10.374
1995	9.74
1996	10.198
1997	10.047
1998	9.664
1999	9.539
2000	9.367
2001	9.246
2002	8.867
2003	8.748
2004	8.335
2005	8.048
2006	7.904
2007	8.049
2008	7.917
2009	7.087
2010	7.019
2011	7.46
2012	7.509
2013	7.39
2014	7.436
2015	7.21
2016	6.939
2017	6.93
2018	6.918
2019	6.919
2020	6.879
2021	6.846
2022	6.824