Year	Percent
1991	8.354
1992	8.642
1993	9.077
1994	8.93
1995	9.008
1996	8.327
1997	7.551
1998	7.136
1999	7.089
2000	6.734
2001	6.375
2002	6.139
2003	5.746
2004	5.449
2005	5.574
2006	5.226
2007	5.061
2008	4.734
2009	1.364
2010	0.852
2011	0.605
2012	0.453
2013	0.339
2014	0.271
2015	0.222
2016	0.186
2017	0.396
2018	0.388
2019	0.375
2020	0.366
2021	0.353
2022	0.341