Year Percent 1990 53.544 1991 53.827 1992 54.226 1993 54.473 1994 54.849 1995 55.115 1996 55.284 1997 55.544 1998 55.684 1999 55.772 2000 55.905 2001 56.029 2002 56.162 2003 56.259 2004 56.309 2005 56.292 2006 56.257 2007 56.182 2008 56.099 2009 56.069 2010 56.099 2011 56.18 2012 56.318 2013 56.477 2014 56.614 2015 56.718 2016 56.797 2017 56.829 2018 56.83 2019 56.83 2020 56.844 2021 56.874 2022 56.917 2023 56.949 2024 56.937 2025 56.861 2026 56.736 2027 56.555 2028 56.348 2029 56.159 2030 56.013