Year % 1994 18.45 1995 18.1 2001 18.65 2002 18.52 2003 19.19 2004 19.19 2005 19.16 2006 19.21 2007 18.78 2008 18.72 2009 18.95 2010 18.72 2011 18.87 2012 18.88 2013 18.75 2014 18.91 2019 18.56