Year	Percent
1997	2.01087
1998	2.09451
1999	2.59828
2000	3.03814
2001	2.61112
2002	3.58589
2003	2.99785
2004	3.28295
2005	2.88012
2006	3.0888
2007	2.488
2008	2.01871
2009	2.19184
2010	2.36712
2011	2.39047
2012	2.33802
2013	2.53265
2014	2.4058
2015	2.59179
2016	2.33776
2017	1.88482