Year % 1991 57.6 1995 54.5 1996 55.5 1998 57.5 1999 55.7 2000 55.8 2001 55.5 2002 55.7 2003 54.2 2004 52.3 2005 53.2 2006 51.3 2007 51.2 2008 52.4 2009 51.6 2010 49.4 2011 48.7 2012 48.2 2013 49.6 2014 48 2015 47.2 2016 46.4 2017 44.7 2018 45.2 2019 45.6 2021 45 2022 44.8