Year Percent 1991 47.178 1992 47.467 1993 46.049 1994 43.927 1995 46.725 1996 50.027 1997 51.268 1998 52.053 1999 53.77 2000 50.343 2001 51.497 2002 52.933 2003 53.591 2004 52.233 2005 53.909 2006 54.119 2007 53.134 2008 55.201 2009 56.949 2010 56.899 2011 56.781 2012 56.107 2013 54.656 2014 55.818 2015 53.973 2016 53.868 2017 53.65 2018 53.556 2019 53.339 2020 53.185 2021 53.044 2022 52.92