Year Percent 1990 2.798 1991 2.957 1992 3.1 1993 2.892 1994 2.697 1995 2.515 1996 2.345 1997 2.186 1998 2.038 1999 1.899 2000 1.77 2001 1.52 2002 1.81 2003 2.29 2004 1.86 2005 1.43 2006 1.46 2007 1.56 2008 2.12 2009 1.86 2010 1.63 2011 1.57 2012 1.87 2013 2.18 2014 2.57 2015 2.73 2016 2.86 2017 2.858 2018 2.857 2019 2.855 2020 2.854 2021 2.852 2022 2.851 2023 2.849 2024 2.848 2025 2.846 2026 2.845 2027 2.843 2028 2.842 2029 2.84 2030 2.838