Year Percent 1990 59.405 1991 59.41 1992 59.393 1993 59.321 1994 59.297 1995 59.339 1996 59.306 1997 59.35 1998 59.381 1999 59.384 2000 59.4 2001 59.405 2002 59.409 2003 59.409 2004 59.409 2005 59.404 2006 59.404 2007 59.393 2008 59.378 2009 59.361 2010 59.331 2011 59.27 2012 59.217 2013 59.182 2014 59.108 2015 59.049 2016 59.043 2017 59.026 2018 59.01 2019 58.993 2020 58.976 2021 58.96 2022 58.943 2023 58.926 2024 58.91 2025 58.893 2026 58.876 2027 58.86 2028 58.843 2029 58.826 2030 58.81