Year	Percent
1980	2
1986	2
1987	1.7
1991	1.7
1992	1.6
1993	1.5
1994	1.5
1995	1.1
1996	1
1997	1.1
1998	1.1
1999	1.1
2000	0.9
2001	0.7
2002	0.9
2003	1
2004	1.1
2005	1.2
2006	1.2
2007	1.3
2008	1.3
2009	1.3
2010	1.6
2011	1.7
2012	1.7
2013	1.8
2014	1.8
2016	1.8