Year	Percent
1991	5.91
1993	7.22
1994	5.74
1995	4.94
1996	5.1
1997	4.14
1998	4.17
2001	7.54
2002	5.37
2003	3.61
2004	3.45
2005	3.54
2006	2.62
2007	3.83
2008	3.97
2009	6.04
2010	6.68
2011	6.78
2012	6.21
2013	6.27
2014	4.7
2015	4.24