Year	Percent
1984	22.5
1992	20.7
1994	20.5
1996	28.5
1998	26.2
2000	22.4
2002	19.8
2004	16.2
2005	18.3
2006	12.8
2008	13.8
2010	14
2012	13.1
2014	14.2
2016	11.2