Year Percent 1990 0 1995 2.20077 1996 2.85845 1997 3.48054 1998 4.07172 1999 5.30068 2000 6.48223 2001 8.89929 2002 12.5 2003 17.22865 2004 24.26654 2005 27 2006 30 2007 34 2008 38 2009 42 2010 47 2011 52 2012 58 2013 63.4 2014 67.78 2015 70 2016 73