Year	Percent
1991	11.368
1992	12.511
1993	13.386
1994	13.174
1995	12.8
1996	12.91
1997	12.923
1998	11.309
1999	13.902
2000	13.934
2001	9.072
2002	9.066
2003	9.079
2004	10.008
2005	9.372
2006	9.358
2007	8.557
2008	8.548
2009	8.313
2010	8.471
2011	8.841
2012	8.185
2013	7.833
2014	8.141
2015	7.873
2016	7.777
2017	7.879
2018	7.761
2019	7.619
2020	7.426
2021	7.188
2022	6.912