Year	Percent
1998	37.16649
1999	37.26456
2000	37.21645
2001	33.88396
2002	34.84693
2003	33.90777
2004	34.44314
2005	34.25592
2006	33.52993
2007	31.34546
2008	30.44642
2009	31.87938
2010	32.50973
2011	29.22917
2012	29.11228
2013	27.84495
2014	31.12335