Year Percent 1990 3.41 1991 2.14 1992 2.56 1993 3.47 1994 3.559 1995 3.65 1996 3.14 1997 4.42 1998 3.93 1999 4.22 2000 4.76 2001 4.535 2002 4.32 2003 4.61 2004 4.1 2005 4.15 2006 5.32 2007 4.22 2008 4.18 2009 4.009 2010 3.845 2011 3.687 2012 3.536 2013 3.39 2014 3.25 2015 3.116 2016 3.156 2017 3.088 2018 3.02 2019 2.952 2020 2.884 2021 2.816 2022 2.748 2023 2.68 2024 2.612 2025 2.544 2026 2.476 2027 2.408 2028 2.34 2029 2.272 2030 2.205