Year	Percent
1992	2.38872
1993	2.85805
1994	3.22542
1995	3.40271
1996	3.5236
1997	3.62404
1998	3.75246
1999	3.63723
2000	3.41801
2001	3.02903
2002	2.86866
2003	2.71175
2004	2.07629
2005	1.97766
2006	1.73883
2007	1.50336
2008	1.65451
2009	1.95462
2010	2.20186
2011	2.28347
2012	3.06168
2013	3.63502
2014	3.96355
2015	3.62886
2016	3.53906
2017	3.44007