Year Percent 1990 3.00167 1991 3.04374 1992 3.39837 1993 3.41602 1994 3.42634 1995 4.86592 1996 5.39219 1997 5.18574 1998 4.66726 1999 4.25928 2000 3.88906 2001 2.72267 2002 2.65815 2003 2.65964 2004 2.02389 2005 2.4749 2006 2.44641 2007 2.33838 2008 2.40649 2009 2.30726 2010 2.30975 2011 2.37076 2012 2.31133 2013 2.28548 2014 2.27193 2015 2.17517 2016 2.08207 2017 2.0035 2018 2.27193 2019 2.26457 2020 2.39242