Year Percent 1991 11.153 1992 11.321 1993 11.36 1994 11.616 1995 11.893 1996 12.05 1997 12.292 1998 13.092 1999 13.545 2000 14.259 2001 14.587 2002 15.035 2003 16.103 2004 17.042 2005 18.061 2006 19.313 2007 20.121 2008 21.067 2009 22.098 2010 22.865 2011 23.789 2012 25.034 2013 26.304 2014 27.39 2015 28.853 2016 29.719 2017 30.667 2018 31.776 2019 32.819 2020 33.807 2021 34.838 2022 35.635