Year	Percent
1991	18.319
1992	13.357
1993	16.245
1994	21.011
1995	16.912
1996	16.379
1997	19.257
1998	21.133
1999	20.005
2000	20.843
2001	20.53
2002	19.009
2003	18.118
2004	16.974
2005	15.646
2006	14.343
2007	13.814
2008	10.661
2009	10.155
2010	9.9
2011	8.848
2012	8.223
2013	7.732
2014	7.158
2015	6.805
2016	6.465
2017	6.304
2018	6.038
2019	5.798
2020	5.526
2021	5.258
2022	4.993