Year	Percent
1991	52.103
1992	48.526
1993	47.442
1994	47.54
1995	44.274
1996	42.228
1997	39.32
1998	36.034
1999	32.227
2000	29.08
2001	28.987
2002	27.844
2003	27.348
2004	25.303
2005	20.648
2006	15.39
2007	11.105
2008	8.498
2009	16.348
2010	30.37
2011	30.771
2012	26.636
2013	30.8
2014	30.298
2015	23.68
2016	18.056
2017	18.25
2018	18.049
2019	17.527
2020	16.969
2021	16.417
2022	15.924