Year	Percent
1991	9.563
1992	9.282
1993	8.961
1994	10.438
1995	8.993
1996	8.427
1997	8.807
1998	8.078
1999	7.557
2000	6.761
2001	6.026
2002	5.563
2003	5.118
2004	5.125
2005	4.813
2006	4.848
2007	3.528
2008	3.681
2009	3.862
2010	3.81
2011	3.683
2012	3.44
2013	3.58
2014	3.437
2015	3.436
2016	3.262
2017	3.829
2018	3.83
2019	3.789
2020	3.764
2021	3.734
2022	3.703