Year	Percent
1992	10.969
1993	13.526
1994	12.064
1995	11.311
1996	10.8037
1997	9.8657
1998	9.5943
1999	7.5047
2000	7.1904
2001	6.3186
2002	6.0452
2003	6.127
2004	5.8114
2005	6.9865
2006	7.1411
2007	7.1314
2008	7.6596
2009	10.2753
2010	11.6114
2011	11.0681
2012	11.3409
2013	10.2114
2014	7.5658
2015	6.6218
2016	5.1206
2017	3.8088