Year	Percent
1991	2.6
1995	3.7
1996	3.5
1998	2
1999	2.5
2000	3.2
2001	3.1
2002	3
2003	2.8
2004	3.7
2005	3.8
2006	4.8
2007	5.2
2008	4.6
2009	4.9
2010	5.1
2011	5.6
2012	5.7
2013	5.5
2014	5.8
2015	6.1
2016	5.9