Year	Percent
1991	10.939
1992	11.035
1993	10.866
1994	10.507
1995	9.908
1996	9.941
1997	9.547
1998	9.401
1999	9.047
2000	8.927
2001	8.52
2002	8.806
2003	8.677
2004	8.595
2005	8.809
2006	8.76
2007	9.046
2008	9.317
2009	9.333
2010	9.501
2011	9.577
2012	8.894
2013	8.787
2014	9.208
2015	9.276
2016	9.207
2017	9.296
2018	9.294
2019	9.309
2020	9.315
2021	9.333
2022	9.353