Year	Percent
1998	26.1579
1999	19.5797
2000	21.7086
2001	24.0451
2002	25.3917
2003	26.6021
2004	30.7948
2005	18.4285
2006	16.0445
2007	9.9504
2008	13.0852
2009	29.2099
2010	34.7579
2011	30.6004
2012	29.4786
2013	24.9349
2014	19.9621
2015	14.1542
2016	12.142
2017	15.4243