Year Percent 1992 2.18923 1993 2.45902 1994 1.38282 1995 2.25173 1996 1.98038 1997 1.90834 1998 1.93158 1999 2.19409 2000 1.90069 2001 3.98491 2002 3.89365 2003 3.73474 2004 3.70313 2005 3.71168 2006 3.6991 2007 3.68202 2008 3.66319 2009 3.64544 2010 3.63407 2011 3.13293 2012 3.13138 2013 3.1325 2014 3.1336 2015 3.13359 2016 3.08331 2017 3.08449 2018 3.10784 2019 3.11806 2020 3.20385