Year	Percent
1987	9.8
1994	10.1
2002	10.1
2003	10
2004	10.1
2005	10
2006	10.6
2007	11
2008	10.9
2009	10.8
2010	11
2011	10.6
2012	10.5
2013	10.5
2014	10.2
2015	9.9
2016	9.9