Year	Percent
1991	10.608
1992	10.684
1993	10.667
1994	10.603
1995	10.507
1996	10.411
1997	10.279
1998	10.151
1999	10.031
2000	9.863
2001	9.678
2002	9.506
2003	9.316
2004	9.145
2005	8.994
2006	8.938
2007	8.867
2008	8.866
2009	8.872
2010	8.843
2011	8.765
2012	8.697
2013	8.626
2014	8.563
2015	8.496
2016	8.531
2017	8.395
2018	8.269
2019	8.152
2020	8.034
2021	7.913
2022	7.786