Year	Percent
1998	12.732
1999	13.2604
2000	13.2328
2001	11.9777
2002	11.9813
2003	10.5358
2004	10.3137
2005	9.4736
2006	5.8299
2007	5.321
2008	6.9481
2009	13.2655
2010	14.8625
2011	12.3257
2012	12.5395
2013	10.2588
2014	9.4765
2015	8.6018
2016	8.7304
2017	7.4735