Year	Percent
1991	25.65
1992	24.038
1993	22.786
1994	23.054
1995	21.693
1996	21.607
1997	21.803
1998	22.536
1999	21.046
2000	20.356
2001	17.193
2002	15.583
2003	15.51
2004	16.523
2005	16.144
2006	14.423
2007	14.139
2008	14.629
2009	9.813
2010	9.955
2011	9.886
2012	11.011
2013	9.088
2014	9.848
2015	10.071
2016	9.491
2017	9.091
2018	9.061
2019	8.974
2020	8.959
2021	8.889
2022	8.753