Year Percent 1990 0 1996 0.00883 1997 0.01724 1998 0.02523 1999 0.04104 2000 0.06408 2001 0.0899 2002 0.32046 2003 0.55858 2004 1.28614 2005 3.54916 2006 5.54504 2007 6.77 2008 8 2009 9.3 2010 11.5 2011 13.8 2012 16.1 2013 19.1 2014 21 2015 24.5 2016 25.67