Year Percent 1990 69.231 1991 69.483 1992 69.667 1993 69.937 1994 69.61 1995 69.442 1996 69.457 1997 69.394 1998 69.128 1999 69.259 2000 69.075 2001 68.927 2002 67.392 2003 68.042 2004 68.602 2005 68.913 2006 69.187 2007 70.299 2008 71.26 2009 68.648 2010 68.465 2011 70.344 2012 70.841 2013 71.146 2014 72.546 2015 73.912 2016 74.061 2017 74.453 2018 74.833 2019 75.174 2020 75.464 2021 75.71 2022 75.911 2023 76.077 2024 76.226 2025 76.367 2026 76.506 2027 76.637 2028 76.761 2029 76.883 2030 77.007