Year	Percent
1991	12.06
1992	12.224
1993	13.184
1994	14.902
1995	15.878
1996	15.968
1997	15.978
1998	16.464
1999	13.763
2000	13.781
2001	15.584
2002	15.58
2003	15.587
2004	13.81
2005	13.141
2006	12.814
2007	12.334
2008	11.858
2009	11.677
2010	11.522
2011	12.028
2012	13.489
2013	11.345
2014	10.856
2015	10.685
2016	10.402
2017	10.472
2018	10.477
2019	10.413
2020	10.288
2021	10.159
2022	9.995