Year Percent 1991 38.705 1992 40.401 1993 41.341 1994 39.87 1995 39.027 1996 38.589 1997 39.552 1998 40.024 1999 38.838 2000 40.077 2001 40.466 2002 38.328 2003 37.556 2004 40.662 2005 43.167 2006 45.078 2007 46.123 2008 46.937 2009 46.498 2010 45.841 2011 46.367 2012 46.32 2013 46.628 2014 47.145 2015 47.108 2016 45.933 2017 45.932 2018 45.88 2019 45.992 2020 46.033 2021 46.049 2022 46.049