Year % of total 1986 71.1 1990 80.6 1995 84.5 1998 91.3 1999 92.1 2000 86.1 2001 93.1 2002 94.5 2003 95 2004 95.6 2005 90.7 2006 97.1 2007 97.8 2008 98.1 2009 98.6 2010 94.8 2011 99.2 2012 98.7 2013 98.7 2014 98.9 2015 99 2016 95.9 2017 99.3 2018 98.4 2019 98.8