Year	Percent
1987	1.7
1994	2.6
2002	1.7
2003	3.7
2004	2.1
2005	2.6
2006	1.9
2007	1.4
2008	0.6
2009	0.9
2010	0.8
2011	0.3
2012	0.3
2013	0.3
2014	0.3
2015	0.3
2016	0.2