Year	Percent
1997	4.8941
1998	4.9288
1999	5.4527
2000	6.6503
2001	5.9055
2002	7.0102
2003	5.6861
2004	5.2038
2005	5.9527
2006	5.4706
2007	4.8707
2008	4.0071
2009	5.1689
2010	5.68
2011	5.9267
2012	5.5019
2013	5.6782
2014	5.5362
2015	5.1641
2016	4.3584
2017	3.2618