Year Percent 1990 0 1995 0.04074 1996 0.076 1997 0.50399 1998 1.00286 1999 1.49733 2000 2.48557 2001 3.46818 2002 17.33 2003 19.07 2004 24.44 2005 26.45 2006 28.62 2007 36.3 2008 46.04 2009 51.77 2010 51.9 2011 56.7 2012 57.44995 2013 65.24 2014 68.06 2015 70.3802 2016 72.15681