Year Percent 1990 66.092 1991 65.971 1992 65.87 1993 65.958 1994 65.993 1995 65.933 1996 66.415 1997 66.851 1998 66.815 1999 67.362 2000 67.739 2001 67.545 2002 68.038 2003 67.922 2004 68.296 2005 68.679 2006 69.1 2007 68.854 2008 69.192 2009 69.299 2010 69.2 2011 69.454 2012 70.019 2013 70.672 2014 71.165 2015 71.559 2016 72.055 2017 72.222 2018 72.364 2019 72.48 2020 72.573 2021 72.622 2022 72.638 2023 72.642 2024 72.665 2025 72.726 2026 72.806 2027 72.922 2028 73.07 2029 73.243 2030 73.435