Year Percent 1990 13.66757 1991 12.58094 1992 11.75279 1993 10.89334 1994 10.19177 1995 12.43865 1996 11.96526 1997 12.10934 1998 11.81221 1999 11.53282 2000 12.52671 2001 9.17742 2002 9.0287 2003 9.03692 2004 8.61589 2005 8.31658 2006 7.84849 2007 6.93597 2008 6.77767 2009 6.45908 2010 6.37073 2011 6.2471 2012 6.563 2013 6.26933 2014 5.66604 2015 4.97517 2016 4.55883 2017 4.29823 2018 3.74852 2019 4.15501 2020 3.96896