Year	Percent
1979	3.9
1989	0.8
1991	1.2
1995	1.4
1997	1.7
1998	1.6
1999	1.9
2000	2.1
2001	1.9
2002	2.5
2003	2.4
2004	2.6
2005	2.7
2006	2.5
2007	2.9
2008	3
2009	3.5
2010	3.3
2011	3.4
2012	3.2
2013	3.3
2014	3.3
2015	3.4
2016	3.3