Year	Percent
1998	14.2806
1999	13.4235
2000	17.5247
2001	17.5392
2002	12.7405
2003	11.5012
2004	8.838
2005	7.4425
2006	5.3841
2007	3.9222
2008	5.3778
2009	15.7386
2010	20.0387
2011	16.5167
2012	14.1011
2013	11.9299
2014	11.1012
2015	9.473
2016	8.4428
2017	8.1383