Year	Percent
1998	11.6887
1999	12.1951
2000	13.3241
2001	13.8148
2002	12.8193
2003	10.6507
2004	10.7098
2005	8.3977
2006	5.3449
2007	4.0242
2008	5.0182
2009	9.8224
2010	13.5308
2011	12.1322
2012	11.0641
2013	10.0935
2014	8.7603
2015	7.7975
2016	6.3513
2017	5.1311