Year	Percent
1991	14.329
1992	13.99
1993	13.627
1994	15.315
1995	13.635
1996	12.994
1997	13.484
1998	12.541
1999	11.961
2000	11.034
2001	10.116
2002	9.504
2003	8.901
2004	8.837
2005	8.388
2006	8.367
2007	6.916
2008	7.064
2009	7.134
2010	7.006
2011	6.791
2012	6.43
2013	6.646
2014	6.424
2015	6.413
2016	6.142
2017	6.968
2018	6.965
2019	6.902
2020	6.859
2021	6.811
2022	6.758