Year % of total 1995 100 1999 91 2000 98 2002 100 2003 100 2004 100 2005 100 2006 100 2007 100 2008 100 2009 100 2011 100 2012 98.9 2013 98.6 2014 99.8 2015 99 2016 99.1 2018 99 2019 98 2020 98.4