Year	Percent
1984	8.1
1992	7.7
1994	6.6
1996	11.2
1998	11.2
2000	8.9
2002	6.6
2004	5.2
2005	6.2
2006	3.4
2008	4.1
2010	4.2
2012	3.4
2014	4.1
2016	2.5