Year	Percent
1991	12.049
1992	11.743
1993	11.393
1994	10.886
1995	10.852
1996	10.835
1997	10.355
1998	10.384
1999	10.886
2000	10.558
2001	11.974
2002	12.91
2003	12.708
2004	12.533
2005	12.27
2006	12.252
2007	11.345
2008	11.21
2009	11.225
2010	9.96
2011	10.159
2012	10.249
2013	10.18
2014	9.171
2015	8.999
2016	9.002
2017	9.019
2018	9.007
2019	8.994
2020	8.98
2021	8.971
2022	8.962