Year	Percent
1991	11.69
1992	12.218
1993	12.912
1994	13.554
1995	13.734
1996	11.844
1997	10.683
1998	10.269
1999	9.417
2000	8.433
2001	8.273
2002	7.597
2003	6.74
2004	6.054
2005	6.08
2006	5.598
2007	5.749
2008	6.048
2009	6.916
2010	6.422
2011	5.665
2012	5.214
2013	4.627
2014	4.484
2015	4.482
2016	4.378
2017	6.808
2018	6.702
2019	6.639
2020	6.566
2021	6.474
2022	6.384