Year Percent 1992 0.21224 1993 0.21198 1994 0.21007 1995 1.23914 1996 1.58482 1997 0.67425 1998 0.66196 1999 0.64905 2000 0.44596 2001 0.43129 2002 0.41715 2003 0.4038 2004 0.64816 2005 0.68957 2006 0.88737 2007 0.87659 2008 0.86746 2009 0.81529 2010 0.79606 2011 0.77804 2012 0.7611 2013 0.74427 2014 0.72785 2015 0.71169 2016 0.69556 2017 0.71622 2018 0.69966 2019 0.6995 2020 0.6906