Year Percent 1991 5.289 1992 5.19 1993 4.853 1994 5.135 1995 5.347 1996 5.384 1997 5.652 1998 5.598 1999 5.602 2000 5.041 2001 5.041 2002 3.714 2003 3.804 2004 3.782 2005 3.868 2006 3.877 2007 3.855 2008 3.863 2009 3.995 2010 3.92 2011 4.156 2012 4.59 2013 4.754 2014 4.966 2015 4.941 2016 4.824 2017 4.744 2018 4.716 2019 4.677 2020 4.637 2021 4.607 2022 4.578