Year	Percent
1991	23.448
1992	24.115
1993	24.165
1994	24.013
1995	22.772
1996	22.219
1997	20.586
1998	19.494
1999	18.501
2000	18.909
2001	19.216
2002	19.8
2003	19.12
2004	18.644
2005	17.966
2006	16.41
2007	15.206
2008	14.087
2009	13.382
2010	13.354
2011	13.44
2012	13.269
2013	12.848
2014	12.484
2015	12.487
2016	11.546
2017	11.563
2018	11.34
2019	11.134
2020	10.926
2021	10.715
2022	10.507