Year Percent 1991 42.38 1992 42.361 1993 42.378 1994 42.414 1995 42.414 1996 42.461 1997 42.505 1998 42.545 1999 42.624 2000 42.764 2001 42.811 2002 42.901 2003 43.028 2004 43.159 2005 43.273 2006 43.406 2007 43.556 2008 43.728 2009 43.956 2010 44.181 2011 44.468 2012 44.825 2013 45.186 2014 45.54 2015 45.872 2016 46.088 2017 46.167 2018 46.229 2019 46.298 2020 46.393 2021 46.495 2022 46.614