Year	Percent
1998	9.37312
1999	8.02688
2000	11.90069
2001	11.18678
2002	10.85096
2003	11.38542
2004	8.70977
2005	8.11602
2006	6.83724
2007	8.84398
2008	8.83239
2009	10.67857
2010	11.55246
2011	11.12783
2012	12.94459
2013	13.68159
2014	14.70369
2015	17.66866
2016	16.42419