Year	Percent
1991	5.45
1992	5.26
1993	5.36
1994	4.56
1995	4.24
1996	2.5
1997	3.69
1998	2.45
1999	2.18
2000	1.64
2001	1.39
2002	1.32
2003	1.3
2004	1.4
2005	2.72
2006	2.24
2007	2.32
2008	3.3
2009	1.8
2010	1.93
2011	1.82
2012	1.63
2013	1.55
2014	1.51
2015	2.24
2016	2.04
2017	1.88