Year Percent 1991 25.611 1992 25.6 1993 25.605 1994 25.644 1995 25.626 1996 25.715 1997 25.774 1998 25.79 1999 25.845 2000 25.966 2001 25.965 2002 25.998 2003 25.981 2004 26.014 2005 26.024 2006 26.065 2007 26.193 2008 26.27 2009 26.355 2010 26.386 2011 26.477 2012 26.566 2013 26.703 2014 26.84 2015 26.985 2016 27.054 2017 27.086 2018 27.123 2019 27.159 2020 27.204 2021 27.253 2022 27.298