Year	Percent
1998	3.73
1999	4.12
2000	3.02
2001	3.44
2002	3.64
2003	3.8
2004	3.09
2005	2.96
2006	2.78
2007	1.94
2008	1.46
2009	1.63
2010	1.61
2011	1.4
2012	1.31
2013	1.17
2014	1.26
2015	1.15
2016	0.92
2017	0.88