Year Percent 1990 3.6 1991 3.4 1992 3.44 1993 3.53 1994 3.42 1995 3.35 1996 3.38 1997 3.61 1998 3.53 1999 3.4 2000 3.31 2001 3.43 2002 3.81 2003 4.28 2004 4.48 2005 4.98 2006 5.2 2007 5.62 2008 6.71 2009 6.68 2010 7.45 2011 7.98 2012 8.73 2013 9.12 2014 9.36 2015 9.54 2016 10.15 2017 10.328 2018 10.507 2019 10.685 2020 10.864 2021 11.042 2022 11.221 2023 11.399 2024 11.577 2025 11.756 2026 11.934 2027 12.113 2028 12.291 2029 12.469 2030 12.648