Year Percent 1990 77.079 1991 76.962 1992 76.525 1993 76.69 1994 76.807 1995 76.771 1996 76.831 1997 76.689 1998 75.657 1999 74.588 2000 73.482 2001 72.335 2002 71.153 2003 69.94 2004 68.709 2005 70.867 2006 72.787 2007 74.492 2008 76.002 2009 76.053 2010 75.755 2011 75.366 2012 74.299 2013 74.059 2014 74.569 2015 74.71 2016 73.98 2017 74.125 2018 74.267 2019 74.397 2020 74.508 2021 74.594 2022 74.667 2023 74.723 2024 74.761 2025 74.78 2026 74.767 2027 74.741 2028 74.708 2029 74.676 2030 74.652