Year	Percent
1996	20.72
1997	15.37
1998	15.3642
1999	14.1824
2000	14.985
2001	15.1253
2002	14.8564
2003	12.0998
2004	11.1725
2005	10.0924
2006	7.3091
2007	6.5106
2008	8.3822
2009	20.8986
2010	22.7466
2011	18.6361
2012	16.1615
2013	12.6
2014	11.8479
2015	11.0938
2016	10.8952
2017	9.7579