Year Percent 1992 3.824 1993 4.771 1994 7.318 1995 8.642 1996 8.857 1997 10.695 1998 11.777 1999 11.85 2000 9.609 2001 8.317 2002 7.35 2003 7.441 2004 6.878 2005 6.424 2006 6.457 2007 5.377 2008 5.507 2009 7.736 2010 6.7686 2011 5.9609 2012 4.8327 2013 4.9445 2014 4.643 2015 4.9546 2016 4.8874 2017 4.5397