Year Percent 1991 23.578 1992 23.737 1993 24.048 1994 24.224 1995 24.471 1996 24.436 1997 24.43 1998 21.776 1999 21.835 2000 21.881 2001 21.954 2002 21.988 2003 21.921 2004 21.995 2005 21.968 2006 21.953 2007 21.972 2008 21.962 2009 22.809 2010 22.21 2011 22.303 2012 23.281 2013 25.003 2014 24.366 2015 24.973 2016 25.145 2017 25.764 2018 26.266 2019 26.525 2020 26.504 2021 26.188 2022 26.083