Year	Percent
1997	5.8869
1998	5.4709
1999	5.5329
2000	6.3751
2001	6.0068
2002	7.5944
2003	6.3781
2004	6.1537
2005	6.4293
2006	6.1118
2007	5.4087
2008	4.67
2009	5.8394
2010	6.175
2011	6.4637
2012	6.0765
2013	6.3051
2014	6.0927
2015	5.848
2016	4.9807
2017	4.0374