Year	Percent
1991	12.862
1992	13.079
1993	13.076
1994	12.163
1995	13.628
1996	11.703
1997	11.302
1998	12.191
1999	11.153
2000	10.916
2001	9.895
2002	10.313
2003	9.62
2004	8.092
2005	7.917
2006	7.277
2007	7.906
2008	8.403
2009	9.507
2010	11.11
2011	10.467
2012	9.858
2013	9.699
2014	10.257
2015	10.039
2016	9.395
2017	9.252
2018	9.219
2019	9.159
2020	9.1
2021	9.039
2022	8.973