Year	Percent
1991	33.397
1992	32.679
1993	32.949
1994	30.35
1995	30.298
1996	29.924
1997	28.402
1998	28.446
1999	26.464
2000	26.821
2001	25.694
2002	27.097
2003	24.999
2004	24.918
2005	24.121
2006	23.315
2007	22.103
2008	20.343
2009	18.128
2010	17.308
2011	15.785
2012	14.675
2013	14.149
2014	13.562
2015	12.81
2016	12.21
2017	12.13
2018	11.979
2019	11.791
2020	11.582
2021	11.378
2022	11.139