Year Percent 1991 27.723 1992 27.504 1993 27.801 1994 28.234 1995 27.698 1996 28.295 1997 27.512 1998 28.06 1999 27.639 2000 26.553 2001 26.421 2002 24.23 2003 27.079 2004 28.33 2005 27.589 2006 26.373 2007 26.653 2008 25.029 2009 22.625 2010 23.263 2011 22.727 2012 22.706 2013 21.494 2014 22.316 2015 23.317 2016 23.099 2017 22.957 2018 23.289 2019 23.533 2020 23.817 2021 24.067 2022 24.17