Year	Percent
1998	17.90055
1999	18.86803
2000	19.39073
2001	18.76975
2002	21.3041
2003	19.25544
2004	19.35567
2006	33.63857
2007	20.95946
2008	26.43923
2009	29.12414
2010	25.22584
2011	24.05654
2012	32.56877
2013	36.04189
2014	26.28505