Year Percent 1990 2.84873 1991 2.78002 1992 2.75471 1995 3.60659 1996 3.51379 1997 2.56499 1998 2.52399 1999 2.48568 2000 2.43037 2001 2.31754 2002 2.11223 2003 2.02163 2004 2.15375 2005 2.04809 2006 1.98595 2007 1.91097 2008 1.86967 2009 1.83951 2010 2.11473 2011 2.09503 2012 2.08 2013 2.06231 2014 2.02749 2015 2.05524 2016 2.55812 2017 2.55941 2018 2.5057 2019 2.46263 2020 1.99466