Year	Percent
1991	7.803
1992	8.288
1993	8.93
1994	8.911
1995	9.615
1996	9.468
1997	9.441
1998	9.896
1999	10.703
2000	10.518
2001	10.419
2002	10.754
2003	10.158
2004	9.769
2005	9.148
2006	8.922
2007	8.431
2008	8.205
2009	7.722
2010	7.652
2011	17.646
2012	7.739
2013	14.048
2014	17.181
2015	17.204
2016	17.637
2017	13.276
2018	12.06
2019	11.428
2020	10.227
2021	9.68
2022	9.496