Year Percent 1990 9.636 1991 9.845 1992 10.326 1993 10.828 1994 11.352 1995 11.898 1996 12.465 1997 13.432 1998 14.46 1999 15.555 2000 16.723 2001 17.965 2002 19.281 2003 20.675 2004 22.156 2005 23.732 2006 22.894 2007 22.101 2008 19.455 2009 20.404 2010 19.863 2011 19.297 2012 18.735 2013 18.183 2014 17.647 2015 19.296 2016 21.624 2017 21.42 2018 21.21 2019 20.992 2020 20.766 2021 20.534 2022 20.294 2023 20.043 2024 19.773 2025 19.483 2026 19.175 2027 18.849 2028 18.51 2029 18.165 2030 17.823