Year Percent 1992 1.90509 1993 2.00263 1994 2.29401 1995 2.53147 1996 2.30047 1997 1.96556 1998 1.59958 1999 1.26285 2002 0.55293 2003 0.89849 2004 1.31338 2005 1.44835 2006 1.20636 2007 0.91815 2008 0.71579 2009 0.78067 2010 1.11339 2011 1.27008 2012 1.53219 2013 2.05951 2014 2.2726 2015 2.13553 2016 1.79096 2017 1.38475