Year Percent 1992 2.24723 1993 1.8173 1994 1.65407 1995 1.57303 1996 1.53636 1997 1.40137 1998 1.36118 1999 1.2113 2000 1.09317 2001 1.30048 2002 1.38762 2003 1.4038 2004 1.43065 2005 1.4147 2006 1.53803 2007 1.43967 2008 1.49192 2009 1.59005 2010 1.60805 2011 1.29785 2012 1.17252 2013 1.05316 2014 0.97424 2015 0.9305 2016 1.00491 2017 0.99821