Year	Percent
1997	0.9
1998	0.9
1999	0.9
2000	1.2
2001	1.1
2002	1.1
2003	1.3
2004	1.3
2005	1.2
2006	1.2
2007	1.2
2008	1.3
2009	1.4
2010	1.5
2011	1.5
2012	1.5
2013	1.6
2014	1.6
2015	1.6
2016	1.6