Year	Percent
1991	13.704
1992	12.135
1993	11.294
1994	11.671
1995	12.378
1996	11.776
1997	14.889
1998	11.965
1999	12.016
2000	10.601
2001	7.125
2002	8.137
2003	8.335
2004	8.288
2005	6.832
2006	6.11
2007	5.646
2008	5.781
2009	5.34
2010	5.201
2011	4.809
2012	4.286
2013	4.439
2014	4.56
2015	4.329
2016	4.248
2017	3.843
2018	3.666
2019	3.519
2020	3.383
2021	3.254
2022	3.134