Year Percent 1993 0.4054 1994 4.39366 1995 13.25057 1996 13.09144 1997 11.3972 1998 18.82947 1999 21.18901 2000 30.195 2001 31.15374 2002 20.47919 2003 21.88556 2004 17.87042 2005 14.81116 2006 7.64417 2007 9.39774 2008 12.34276 2009 11.43741 2010 24.51631 2011 12.68614 2012 9.82322 2013 10.06966 2014 12.15209 2015 16.81379 2016 18.55322