Year	Percent
1991	17.672
1992	15.091
1993	15.306
1994	15.118
1995	14.458
1996	13.261
1997	14.891
1998	14.996
1999	11.869
2000	11.045
2001	10.644
2002	10.943
2003	10.325
2004	10.771
2005	10.614
2006	9.498
2007	8.617
2008	8.583
2009	8.87
2010	7.766
2011	8.012
2012	7.371
2013	7.805
2014	7.967
2015	6.927
2016	6.94
2017	6.379
2018	5.697
2019	5.377
2020	5.095
2021	4.765
2022	4.506