Year % 1984 42 1987 40.8 1990 41.6 1993 42.4 1996 44.4 1998 41.4 1999 41.4 2000 39.3 2001 39.8 2002 42.2 2003 42.1 2004 42.6 2005 42.8 2006 43.7 2007 44.8 2008 44.3 2009 44.4 2010 45 2011 47.9 2012 48.1 2013 48.6 2014 47.9 2015 47.9 2016 46.5 2017 45.9 2018 45.6 2019 45 2020 45 2021 45.4 2022 45.8 2023 46.3