Year Percent 1991 6.399 1992 6.542 1993 6.595 1994 6.495 1995 6.236 1996 6.919 1997 6.56 1998 6.478 1999 6.134 2000 6.187 2001 7.06 2002 7.687 2003 8.348 2004 9.055 2005 9.53 2006 9.898 2007 10.373 2008 10.853 2009 11.14 2010 12.141 2011 11.784 2012 11.901 2013 11.998 2014 12.18 2015 12.439 2016 12.288 2017 12.506 2018 12.532 2019 12.544 2020 12.588 2021 12.616 2022 12.639