Year	Percent
1998	12.52627
2001	15.10178
2002	15.29519
2003	17.74869
2004	11.12208
2005	22.06145
2006	21.45106
2007	20.39286
2008	22.61005
2009	22.5444
2010	20.96661
2011	18.37428
2012	18.26756
2013	22.36016