Year	Percent
1997	2.07221
1998	1.96701
1999	2.21852
2000	2.60083
2001	2.3042
2002	3.08181
2003	2.54411
2004	2.59458
2005	2.26709
2006	2.41116
2007	1.96943
2008	1.52689
2009	1.69774
2010	1.79138
2011	1.89988
2012	1.87648
2013	2.01015
2014	1.90706
2015	1.9839
2016	1.76122
2017	1.36029