Year	Percent
1992	2.20339
1993	2.29664
1995	4.05931
1996	3.28187
1997	3.9094
1998	3.5281
1999	3.69737
2000	3.56002
2001	3.12725
2002	2.69771
2003	2.72837
2004	2.742
2005	2.87193
2006	2.94761
2007	3.04257
2008	3.39558
2009	4.15705
2010	4.26565
2011	3.85395
2012	3.58377
2013	3.99724
2014	3.94338
2015	4.23923
2016	4.08023
2017	3.96804